*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19800
19810
19820
19830
19840
19858
19860
19871
198823
19892
19905
19914
19923
199317
19940
19958
19960
19971
19980
199916
20000
20010
20020
20031
20040
20050
20061
20071
20080
20098
20102
20114
201255
20134
20142
20151
20163
20174
20180
20191
20200
20212
20221
20230
20244
Total182