*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
19895
19900
19911
19921
19930
19940
19950
19960
19970
19980
19990
20000
20011
20020
20030
200430
20051
20060
20070
20086
20090
20100
20110
20120
20130
20141
20150
20162
20170
Total48