*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
197253
197334
19740
19751
19760
19770
19780
19790
19800
19810
19820
19836
19843
198525
198619
198783
1988141
198938
1990154
1991177
1992191
199374
19946
199510
19961
19976
19982
1999102
200078
200163
200218
20039
200452
200517
200611
200712
200821
20093
20107
20118
20129
201314
201412
201513
201615
201717
20181
Total1506