*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19791
19800
19810
19821
19830
19840
19852
19860
19874
19885
19892
19903
19910
19920
19933
19945
19958
19960
19973
19980
19992
20009
20012
20020
20032
20040
20050
20062
200716
20083
20096
201027
201121
20121
20131
20140
20152
20160
20170
Total131