*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19800
19810
19820
19830
19840
19850
19860
19870
19880
19892
19900
199110
19920
19931
19940
19950
19960
19970
19981
19992
20000
20010
20021
20030
20040
20054
20060
20070
20081
20090
20109
20118
20120
20134
20147
20151
20160
20171
20180
Total52