*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19800
19810
19820
19830
19840
19850
19861
19875
198817
19892
19908
19914
19925
19934
19943
199515
19967
199716
199810
199912
200011
20011
20021
20037
20044
20051
20065
20070
20080
20090
20100
20110
20120
20130
20142
20150
20160
20170
Total141