*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19800
19811
19820
19830
19840
19850
19862
198720
19880
19898
19904
199117
19921
19933
19940
19950
199615
199713
19982
19990
20000
20010
20023
20030
20043
20051
20062
20071
20080
20090
20100
20111
20121
20130
20140
20150
20162
20170
20180
20190
20200
Total100