*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19800
19810
19820
19830
19841
19854
19866
19877
19880
19890
19901
19911
19920
19932
19940
19955
19960
19970
19980
19990
20000
20010
20020
20031
20040
20051
20060
20070
20081
20090
20100
20110
20120
20130
20140
20150
20162
20170
Total32