*Excludes Observations that spanned multiple years

Pre 19700
19700
19712
19720
19730
19740
19750
19760
19770
19780
19790
19800
19810
19820
19830
19840
19850
19860
19873
19880
19890
19903
19913
19921
19930
19943
19950
19960
19970
19980
19991
20001
20010
20021
20030
20040
20050
20060
20071
20081
20091
20100
20111
20120
20130
20140
20150
20160
20170
20180
20190
Total22