*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19801
19810
19820
19830
19840
19851
19861
19870
19880
19890
19900
19910
19922
19930
19940
19954
19960
19970
19981
19991
20001
20012
20020
20030
20041
20053
20060
20070
20080
20091
20100
20111
20120
20130
20140
20153
20165
20178
20180
Total36