*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19801
19810
19820
19830
19841
19850
19861
19875
198811
198914
199020
199154
199212
199330
199430
19957
19961
19972
199810
19992
20000
20017
20023
20038
200413
20056
20060
20075
20088
20092
201027
201125
20120
20130
20140
20150
201612
20172
Total319