*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19721
19730
19740
19750
19760
19770
19780
19790
19800
19810
19820
19830
19840
19851
19860
19870
19880
19892
19901
19911
19923
19931
19941
199527
19961
19974
19988
19992
20005
20010
20023
20030
20040
20053
20060
20070
20082
20090
201056
201162
20127
20132
20141
20150
20160
20170
Total194