*Excludes Observations that spanned multiple years

Pre 19701
19700
19710
1972115
197328
19740
19750
19760
19770
19781
19790
19800
19810
19820
19830
198426
198519
198690
1987105
1988124
1989125
199076
1991193
1992163
199384
199444
199584
199620
199747
199861
1999216
2000205
2001190
200261
200365
200479
2005165
200689
2007100
200890
200982
201084
201188
2012118
201392
2014105
2015117
2016122
201792
20181
Total3567