*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19741
19750
19760
19770
19780
19790
19800
19810
19820
19830
19840
19850
19860
19870
19880
19893
19901
19910
19920
19930
19942
19953
19963
199716
19984
199928
200066
200186
200238
20030
20047
20050
20062
20071
20082
20090
20100
20110
20120
20132
20141
20152
20162
20170
20180
Total270