*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19781
19790
19800
19810
19820
19830
19845
198510
198623
198715
19888
19891
19905
199116
19922
19931
19942
19952
19962
19973
19980
19992
200012
200112
20022
20034
20048
20055
20064
20075
20084
200910
20106
201110
20128
20135
20148
20158
20165
20177
20180
20190
Total221