*Excludes Observations that spanned multiple years

Pre 19701
19700
19711
19720
19730
19740
19751
19760
19770
19781
19790
19800
19810
19821
19834
19840
19850
198637
19871
19881
198912
199014
19916
199210
199311
19942
19957
19961
19979
199816
199915
20001
200117
20025
20033
200452
20058
20062
20071
20088
20091
201010
20118
20120
20130
20141
20150
20165
20170
Total273