*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19781
19790
19800
19810
19820
19831
19840
19850
19860
19871
19880
19890
19903
19910
19920
19930
199411
19955
19963
19970
19987
19994
20000
20012
20020
20031
20043
20052
20060
20072
20085
20093
20105
20110
20120
20130
20140
20150
20160
20170
Total59