*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19722
19730
19740
19750
19760
19770
19780
19790
19800
19810
19820
19830
19840
19850
19861
19874
198813
19891
19902
19911
19922
19936
19944
199526
199623
199736
199815
19997
20005
20014
20023
200310
20043
20051
20062
20072
20080
20090
20100
20110
20120
20130
20140
20150
20160
20170
20180
20190
Total173