How do I make a three-month and six-month moving average for the sample data in excel?

Period	Year	Month	Hotel Occupancy
1	1989	Jan	1697
2	1989	Feb	1701
3	1989	Mar	2838
4	1989	Apr	4182
5	1989	May	4756
6	1989	Jun	5001
7	1989	Jul	5492
8	1989	Aug	5598
9	1989	Sep	4707
10	1989	Oct	4207
11	1989	Nov	3424
12	1989	Dec	2372
13	1990	Jan	2636
14	1990	Feb	1468
15	1990	Mar	3090
16	1990	Apr	3195
17	1990	May	5191
18	1990	Jun	4722
19	1990	Jul	5059
20	1990	Aug	5188
21	1990	Sep	4732
22	1990	Oct	3874
23	1990	Nov	3203
24	1990	Dec	1685
25	1991	Jan	2211
26	1991	Feb	1076
27	1991	Mar	2295
28	1991	Apr	2907
29	1991	May	4168
30	1991	Jun	3479
31	1991	Jul	4425
32	1991	Aug	4633
33	1991	Sep	2976
34	1991	Oct	2974
35	1991	Nov	2148
36	1991	Dec	873
37	1992	Jan	2299
38	1992	Feb	1554
39	1992	Mar	1635
40	1992	Apr	2660
41	1992	May	3906
42	1992	Jun	4016
43	1992	Jul	5631
44	1992	Aug	4400
45	1992	Sep	3801
46	1992	Oct	2571
47	1992	Nov	1886
48	1992	Dec	1139
49	1993	Jan	1674
50	1993	Feb	738
51	1993	Mar	2666
52	1993	Apr	1836
53	1993	May	3645
54	1993	Jun	3802
55	1993	Jul	5628
56	1993	Aug	5170
57	1993	Sep	4307
58	1993	Oct	2746
59	1993	Nov	2256
60	1993	Dec	1250
61	1994	Jan	916
62	1994	Feb	1057
63	1994	Mar	2512
64	1994	Apr	2576
65	1994	May	3608
66	1994	Jun	3906
67	1994	Jul	5786
68	1994	Aug	4890
69	1994	Sep	4179
70	1994	Oct	2777
71	1994	Nov	2359
72	1994	Dec	1521
73	1995	Jan	1629
74	1995	Feb	1249
75	1995	Mar	2054
76	1995	Apr	2589
77	1995	May	3790
78	1995	Jun	3793
79	1995	Jul	6074
80	1995	Aug	4905