*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19800
19810
19821
19831
19840
19850
19860
19870
19880
19890
19900
19913
19920
19933
19940
19951
19961
19973
19981
19990
20006
20011
20020
20030
20040
20051
20060
20070
20081
20090
20106
201119
20125
20130
20143
201512
20168
20174
20180
Total80