*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19721
19730
19740
19750
19760
19770
19780
19790
19800
19810
19820
19831
19840
19850
19860
19870
19880
19890
19900
19910
19920
19930
19940
19950
19960
19970
19980
19990
20000
20010
20020
20030
20040
20050
20060
20070
20081
20092
201012
20119
201215
20136
201410
20159
20163
20170
Total69