*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19771
19780
19790
19800
19810
19820
19831
19840
198513
198612
19877
19889
198914
19905
199121
199211
19933
19940
19950
19967
19973
19988
199930
2000949
200123
200210
200317
2004178
200587
2006269
200738
2008117
200993
2010246
2011248
201275
201358
2014151
2015255
20161068
2017112
20186
Total4145