*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
1972106
197331
19740
19750
19760
19770
19780
19790
19800
19810
19820
19830
198457
198523
198647
1987123
1988130
198938
199072
199195
199232
199330
19942
19950
19965
19974
19981
199928
200057
200142
200217
20034
20043
20054
20063
20073
20086
20092
20105
20114
20128
20139
20145
20159
201611
20179
20180
20190
Total1025