*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19731
19740
19750
19760
19770
19780
19790
19800
19810
19820
19830
19840
19850
19860
19870
19880
19890
19900
19911
19920
19931
19942
19950
19962
19971
19980
19990
20000
20012
20020
20031
20043
20051
200611
20072
20083
20091
20102
20111
20121
20131
20140
20150
20160
20170
Total37