*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19738
19740
19750
19760
19770
19781
19790
19800
19810
19820
19830
19840
19851
19860
19871
19881
19891
19900
19910
19920
19930
19940
19950
19960
19971
19983
19992
20000
20010
20020
20030
20040
20051
20060
20070
20084
20090
20102
2011103
2012163
201347
201460
2015182
2016172
20178
20184
Total765