*Excludes Observations that spanned multiple years

Pre 19700
19701
19711
19720
19730
19740
19750
19760
19772
19780
19791
19800
19810
19820
19831
19840
19851
19861
19879
19880
198918
19905
199110
199215
199322
19947
199534
199641
199753
199828
19999
200013
20014
20029
20036
20047
20057
20067
20076
20082
20090
20100
20110
20121
20130
20140
20150
20162
20170
Total323