*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19800
19810
19820
19830
19840
19850
19862
19870
19880
19891
19900
19911
19922
19930
19940
19951
19960
199714
19980
19992
20001
20010
20020
20031
200432
20051
20060
20070
20089
20090
201024
201129
20120
20132
20143
20151
20162
20170
Total128