*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
19874
19880
19890
19904
19915
19925
19933
19941
19958
19967
19975
19981
19992
20001
20010
20023
20030
20044
20053
20066
20072
20082
20090
20100
20110
20120
20130
20142
20150
20160
20170
Total68