*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19755
19760
19770
19780
19790
19800
19810
19820
19831
19840
19850
19860
19870
19880
19892
19900
19910
19920
19934
19944
199530
19964
199716
19981
199911
20002
20019
200220
20030
20042
200535
20062
20073
20086
20091
20109
20113
20124
20132
20140
20150
20160
20170
Total176