*Excludes Observations that spanned multiple years

Pre 19700
19700
19713
19720
19731
19740
19750
19760
19770
19780
19790
19800
19810
19820
19830
19840
19851
19861
19870
19881
19895
19900
19910
19921
19930
19940
19951
19961
19971
19987
19991
20000
20010
20022
20030
20040
20051
20063
20070
20080
20090
20100
20110
20121
20130
20140
20150
20160
20170
Total31