*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19800
19810
19820
19830
19840
19850
19862
19873
19883
19890
19900
19913
19920
19930
19940
19951
19960
19973
19980
19991
20000
20010
20020
20030
20040
20050
20060
20071
20080
20091
20100
20110
20120
20130
20140
20152
20160
20171
20180
20190
Total21