*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19801
19810
19820
19831
19840
19851
19861
19870
19880
19890
19900
19912
19922
19930
19941
19954
19960
19970
19981
19992
20001
20013
20020
20030
20041
20054
20061
20070
20080
20091
20101
20113
20122
20131
20140
20154
20165
20179
20180
Total52