*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
19876
19885
19892
19900
19910
19920
19930
19940
19957
19960
19970
19980
19991
20001
20011
20020
20030
20040
20050
20060
20077
20080
20090
20101
20110
20120
20130
20140
20150
20160
20170
Total31