*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19800
19810
19820
19830
19840
19850
19861
19870
19880
19892
19900
19910
19922
19930
19940
19951
19960
19970
19980
19991
20000
20015
20020
20031
200433
20052
20060
20070
20080
20090
20102
20110
20120
20130
20140
20151
20160
20170
Total51