I have attached my five stock for this assignment I believe that to obtain the average for the every month is subtract the last closing price with the previous price and divide please assist me in this example please also provide the formula PVA.....

BHP Billiton plc (BBL Date 12/2/2013 11/1/2013 10/1/2013 9/3/2013 8/1/2013 7/1/2013 6/3/2013 5/1/2013 4/1/2013 3/1/2013 2/1/2013 1/2/2013 12/3/2012 11/1/2012 10/1/2012 9/4/2012 8/1/2012 7/2/2012 6/1/2012 5/1/2012 4/2/2012 3/1/2012 2/1/2012 1/30/2012 Open High Low Close Volume Adj Close 59.950001 60.82 56.860001 60.57 571100 53.846584 61.740002 64 59.369999 60.68 445100 53.944374 58.200001 63.779999 56.240002 61.639999 658700 54.797813 60.720001 62.93 58.619999 58.860001 457200 52.326401 58.150002 62.52 57.07 58.080002 698300 50.62426 51.990002 59.240002 49.560001 57.139999 841900 49.804924 58.080002 58.779999 50.82 51.27 950600 44.688457 56.09 61.549999 54.75 57.459999 974700 50.083847 58.200001 60.34 53.48 56.529999 1058200 49.273232 61.84 63.98 58.040001 58.060001 750600 50.606827 69.610001 69.940002 62.540001 63.189999 581700 54.083839 72.290001 72.400002 65.190002 68.639999 643100 58.748455 63.580002 70.559998 62.549999 70.370003 447800 60.229153 64.449997 65.5 59.240002 63.130001 596100 54.03249 63.080002 66.25 61 63.98 683300 54.759998 58.189999 66.650002 56.16 62.459999 970400 53.459042 59.23 62.919998 57.130001 58.77 812400 49.31076 57.560001 59.360001 53.610001 58.259998 902400 48.882847 51.389999 59.389999 51.34 57.189999 1388900 47.985065 64.379997 66.080002 51.540001 52.5 1241900 44.049942 61.5 64.400002 57.84 64.360001 1199500 54.00103 65.279999 65.699997 59.150002 61.380001 995900 51.500675 68.330002 69.959999 63.290001 64.809998 1172300 54.378601 67.360001 68.330002 66.650002 67.330002 1858700 55.566055 Valeant Pharmaceuticals International, Inc. (VRX Date Open High Low Close Volume Adj Close 12/2/2013 108.610001 113.349998 105.169998 113.019997 1026500 113.019997 11/1/2013 106 112.470001 102.93 109.629997 993200 109.629997 10/1/2013 104.040001 115.400002 102.599998 105.720001 1551700 105.720001 9/3/2013 100.260002 106.980003 98.360001 104.330002 1017500 104.330002 8/1/2013 94.449997 105.400002 93.660004 98.339996 1375500 98.339996 7/1/2013 86.889999 94.220001 86.889999 93.599998 1308000 93.599998 6/3/2013 91.690002 91.739998 81.940002 86.080002 2145600 86.080002 5/1/2013 75.339996 96.25 71.989998 91.120003 2341600 91.120003 4/1/2013 75.239998 76.57 69.870003 76.080002 1641000 76.080002 3/1/2013 67.349998 75.099998 66.089996 75.019997 1464200 75.019997 2/1/2013 66.470001 67.980003 64.050003 67.459999 1076600 67.459999 1/2/2013 61.130001 67.129997 59.34 66.32 1565000 66.32 12/3/2012 55.43 61.099998 55.150002 59.77 1690400 59.77 11/1/2012 55.810001 58.150002 52.5 55.279999 1648300 55.279999 10/1/2012 56.209999 59 54.290001 55.93 965100 55.93 9/4/2012 57.639999 61.110001 54.400002 55.27 2179400 55.27 8/1/2012 47.57 52.950001 45.810001 51.27 1710900 51.27 7/2/2012 45.080002 49.299999 44.009998 47.560001 1601500 47.560001 6/1/2012 47.389999 49.200001 42.470001 44.790001 2197200 44.790001 5/1/2012 55.66 59.939999 45.889999 48.66 2741200 48.66 4/2/2012 53.599998 56.599998 52.419998 55.630001 1053200 55.630001 3/1/2012 53.110001 55.799999 52.380001 53.689999 1313200 53.689999 2/1/2012 48.73 53.380001 45.52 52.91 2069500 52.91 1/17/2012 50.310001 51.580002 47.970001 48.490002 2298900 48.490002 BRIC Index MSCI Ishares (BKF) Date 12/2/2013 11/1/2013 10/1/2013 9/3/2013 8/1/2013 7/1/2013 6/3/2013 5/1/2013 4/1/2013 3/1/2013 2/1/2013 1/2/2013 12/3/2012 11/1/2012 10/1/2012 9/4/2012 8/1/2012 7/2/2012 6/1/2012 5/1/2012 4/2/2012 3/1/2012 2/1/2012 1/17/2012 Open High Low Close Volume Adj Close 38.490002 38.630001 36.68 37.400002 117700 35.290833 38.709999 39.59 36.5 38.630001 74400 36.22739 37.34 39.669998 37.34 38.57 76600 36.17112 34.630001 39.040001 34.330002 37.240002 102300 34.923843 35.029999 36 33.540001 34.169998 107200 32.044777 34.16 35.869999 32.799999 34.610001 112900 32.457417 37.720001 38.049999 32.619999 34.049999 187800 31.932243 39.360001 40.5 37.459999 37.52 139200 34.487442 38.869999 39.540001 36.869999 39.5 449500 36.307407 39.560001 41.060001 38.279999 38.849998 120100 35.709942 42.09 42.290001 39.209999 39.880001 102000 36.656693 41.48 42.259998 41.009998 41.939999 131700 38.550194 38.5 40.93 38.099998 40.84 157800 37.539101 38.720001 39.5 36.669998 38.27 89100 35.013859 38.09 39.389999 37.650002 38.150002 99700 34.904072 35.459999 39.259998 35 37.740002 129100 34.528954 36.02 37.5 35.16 35.66 90300 32.625927 35.779999 36.779999 34.049999 35.75 93800 32.708271 34.23 36.93 33.619999 35.869999 118700 32.818058 40.110001 40.599998 33.849998 34.970001 129500 31.41889 40.900002 41.849998 39.360001 40.09 115100 36.018967 43.939999 44.349998 40 40.880001 286100 36.728745 41.700001 44.48 41.689999 43.799999 385100 39.352226 39.240002 41.939999 39.18 41.16 136000 36.980312 BHP Billiton Limited (BHP) Date Open High Low Close Volume Adj Close 12/2/2013 67.239998 67.830002 63.619999 67.059998 1820300 60.060837 11/1/2013 70.919998 72.959999 67.730003 68.220001 1238100 61.09977 10/1/2013 66.089996 72.910004 64.669998 70.690002 1371900 63.311974 9/3/2013 66.040001 70.169998 63.91 66.5 1433300 59.559288 8/1/2013 63.599998 68.480003 62.599998 63.279999 1980900 55.655121 7/1/2013 58.049999 64.989998 55.66 62.73 2062500 55.171391 6/3/2013 65.919998 66.839996 56.580002 57.66 2793200 50.712299 5/1/2013 66.550003 70.800003 64.75 65.32 2507500 57.44931 4/1/2013 68.209999 71.459999 63.189999 67.220001 2958600 59.120373 3/1/2013 74.029999 75.010002 68.43 68.43 2599700 60.184574 2/1/2013 79.449997 80.540001 73.900002 74.860001 2149800 64.828377 1/2/2013 80.209999 80.300003 76 78.720001 1995100 68.17112 12/3/2012 72.440002 78.580002 71.43 78.419998 2228700 67.911316 11/1/2012 70.82 73.32 67.400002 72.040001 2282300 62.386272 10/1/2012 69.260002 72.580002 67.300003 70.739998 2437700 61.260475 9/4/2012 65.330002 73 63 68.610001 2709300 59.415909 8/1/2012 67.059998 70.599998 64.800003 65.800003 2004400 55.98262 7/2/2012 65.620003 67.300003 60.73 66.339996 3326600 56.442047 6/1/2012 60.450001 67.57 59.869999 65.300003 3563800 55.55722 5/1/2012 74.57 76.099998 60.349998 61.529999 3817000 52.349705 4/2/2012 72.629997 74.589996 68.540001 74.300003 3208700 63.21442 3/1/2012 77.25 77.790001 69.959999 72.400002 3163200 61.597897 2/1/2012 80.300003 82.230003 75.199997 76.82 3104200 65.358429 1/30/2012 79.190002 80.459999 78.309998 79.440002 4560900 66.644165 Kforce Inc. (KFRC) Date 12/2/2013 11/1/2013 10/1/2013 9/3/2013 8/1/2013 7/1/2013 6/3/2013 5/1/2013 4/1/2013 3/1/2013 2/1/2013 1/2/2013 12/3/2012 11/1/2012 10/1/2012 9/4/2012 8/1/2012 7/2/2012 6/1/2012 5/1/2012 4/2/2012 3/1/2012 2/1/2012 1/17/2012 Open High Low Close Volume Adj Close 20.200001 21.370001 18.41 20.98 130000 20.076515 19.65 20.530001 19.209999 20.18 133300 19.207144 17.639999 20 16.83 19.690001 147200 18.740767 16.5 17.99 16.24 17.690001 97000 16.837185 16.75 17.23 16.190001 16.27 131400 15.485641 14.69 16.879999 14.69 16.68 108000 15.875875 14.92 15.52 14.04 14.6 152200 13.89615 14 15.11 12.23 14.89 264900 14.172169 16.309999 16.43 14.28 15.12 115600 14.391081 14.41 16.65 14.37 16.370001 182000 15.58082 13.85 16.469999 13.43 14.54 211400 13.839042 14.68 14.85 13.36 13.76 183300 13.096645 13.02 14.92 12.2 14.34 275000 13.648684 11.19 13.02 11.15 12.86 161500 11.336042 11.87 12.11 10.66 11.15 133400 9.828684 11.7 12.82 11.16 11.79 155800 10.392841 11.59 12.99 10.34 11.72 176800 10.331137 13.52 14.43 11.57 11.57 160600 10.198912 12.94 13.55 12.14 13.46 127300 11.864941 14.46 14.82 12.65 13.33 194400 11.750346 14.87 15.4 13.9 14.47 104200 12.755252 14.22 15.02 13.7 14.9 164800 13.134295 12.55 14.56 12.21 14.08 220300 12.411468 12.88 13.1 12.28 12.43 115100 10.957