*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19732
19740
19750
19760
19770
19781
19790
19800
19810
19820
19831
19841
19853
19860
198718
19884
19893
19901
19910
19924
19932
19945
199514
19960
19974
19981
19992
20001
20014
20020
20032
20040
20055
20064
200714
200811
20099
20109
20118
20120
20131
20142
20159
201612
20171
20180
Total158