*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19721
19730
19740
19750
19760
19770
19780
19790
19800
19811
19820
19830
19840
19850
19860
19871
19884
19898
199021
199120
19923
199311
199414
19954
199618
19978
19982
199924
200039
200137
200218
20031
20040
20050
20061
20072
20084
20091
20104
201110
20122
20131
20145
20156
20162
20172
20180
Total275