*Excludes Observations that spanned multiple years

Pre 19701
19701
19715
19720
19730
19740
19751
19760
19771
19789
19793
19804
19810
19824
19830
19848
198561
198612
1987156
1988321
198979
199036
1991193
1992124
1993196
1994141
1995326
1996247
1997101
199817
199967
200096
200197
200253
200352
200490
200579
200666
200768
200881
200976
201056
201184
201279
2013113
201489
201589
201656
201772
20183
20193
20204
20210
20220
Total3520