*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
19890
19900
19910
19920
19931
19941
19950
19960
19970
19980
19992
20000
20011
20021
2003417
2004159
2005170
20068
200717
200823
2009155
20101
20112
20120
20130
20140
20151
20161
20170
20180
Total960