what equation do I use for SP500_r?

Date COST COSTS_PE SP500 SP500_ap 2126 149902 SP500_Pr 109 1.20 2016-10-01 2016-11-01 2016-12-01 2017-01-01 2017-02-01 2017-03-01 2017-04-01 2017-05-01 2017-06-01 2017-07-01 2017-08-01 2017-09-01 2017-10-01 2017-11-01 2017-12-01 2018-01-01 2018-02-01 2018-03-01 2018-04-01 2018-05-01 2018-06-01 2018-07-01 2018-08-01 2018-09-01 2018-10-01 2018-11-01 2018-12-01 2019-01-01 2019-02-01 2019-03-01 2019-04-01 2019-05-01 2019-06-01 2010-07-01 2019-04-01 2019-09-01 2019-10-01 Average Variance ***** Standard Devotion 1MTB (96) 1MTB 0.24 0.000203 0.30 0.000250 0.42 0.000353 0.50 0.000413 0.48 0.000402 0.66 0.000552 0.75 0.000621 0.73 0.000607 0.84 0.000701 0.97 0.000810 0.98 0.000816 0.99 0.000828 1.00 0.000830 0.000908 0.001003 1.30 0.001083 1.38 0.001150 1.64 0.001364 166 0.001384 1.71 0.001422 1.81 0.001504 1.89 0.001578 1.94 0.001617 2.04 0.001697 2.17 0.001811 2.24 0.001867 237 0.001971 2.40 0.002000 2.43 0.002021 0.002045 2.43 0.002021 2.40 0.001997 222 0.001852 215 0.001794 207 0.001723 1.99 0.001655 ** 0.001438 0.001280 NA 0.00000033 0.000574 COST SP 136.945 139 019 148.737 152 304 164.594 156.198 165.354 168.065 155.440 154050 152.340 160.189 157.059 179.826 182.012 190.569 186.687 184 764 193.324 194.383 205.512 215.081 229.261 231.556 225.394 228.007 201.304 212.095 216.157 239.927 243.286 237.390 TER 262.552 273,848 292854 286.881 295.840 0.015145 0.069904 0.023982 0.080694 -0.051010 0.058618 0.016395 -0.075120 -0.008878 -0.011164 0,051523 0.019539 0.144958 0.012156 0.047013 -0.020371 -0.010301 0.046329 0.005478 0.057253 0.046562 0.065929 0.010010 0.026611 0.011593 0.117115 0,053605 0,019152 0.109966 0.014000 -0.024235 0,105994 0,043024 0.069403 0.020395 0.031229 0.022922 000269736 EUR 0,051936 0.014895 0.069551 0.023569 0,080292 -0.051563 0.057996 0.015788 -0.075821 -0.009688 -0.011981 0.050695 -0.020369 0.144050 0.011153 0.045930 -0.021521 -0.011665 0.044946 0.004056 0,055749 0.044984 0,064311 0.008313 -0.028423 0.009726 -0.119085 0.051605 0017131 0107921 0.011979 -0.026232 0.104143 0041230 0067680 0.022051 0.029791 0.002698 0.00269770 0.051939 2198.810059 2238.830078 2278.870117 2363.639893 2362.719971 2384.199951 2411.800049 2423 409912 2470.300049 2471.649902 2519.360107 2575.26001 2584 840088 2673.610107 2823.810059 2713.830078 2640.870117 2648,050049 2705.27002 2718,370117 2816.290039 2901.52002 2913.97998 2711.73999 2760.169922 2506850098 2704 100098 2784 48999 2834399902 2945.830078 2752.060059 2941.76001 2980.379883 2926 459951 2976,73999 3037.560059 2.45