*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
197212
19733
19740
19750
19760
19770
19780
19790
19800
19810
19820
19830
19840
19850
19860
19870
19882
19890
19902
19910
19920
19937
19940
19951
19962
19970
19980
199912
200022
20012
20026
20030
20040
20050
20060
20070
20081
20090
20100
20110
20120
20131
20140
20150
20160
20170
20180
Total73