*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19772
19780
19791
19800
19810
19820
19830
19841
19850
19860
19870
19885
19890
19900
19911
19926
19931
19940
19950
19960
199712
19989
19990
20000
200142
20021
200323
20045
20051
20061
20070
20083
20090
201023
201128
20120
201329
20141
20153
20160
20174
201855
20190
Total257