*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19801
19810
19822
19830
19840
19850
19860
19871
19880
19890
19900
19910
19920
19930
199410
19950
19963
19971
19982
19991
20000
20011
20023
20035
20040
200540
20060
20070
20081
20091
20100
20110
20120
20132
20142
20152
20163
20171
20187
Total89