*Excludes Observations that spanned multiple years

Pre 19700
19700
19711
19720
19730
19740
19750
19760
19770
19780
19790
19800
19810
19820
19830
19840
19851
19860
19870
19880
19890
19902
19913
19921
19931
19940
19950
19960
19970
19980
19990
20000
20010
20020
20030
20041
20051
20061
20071
20081
20092
20100
20110
20120
20130
20141
20150
20161
20170
20180
20190
20200
20210
20220
Total18