*Excludes Observations that spanned multiple years

Pre 19700
19701
19710
19720
19730
19740
19750
19760
19770
19780
19790
19801
19810
19820
19830
19840
19850
19861
19870
19883
19890
19909
19912
19927
19937
19940
19954
19962
19975
19988
19993
20008
20012
20028
20032
20040
20050
20060
20072
20081
20090
20100
20110
20120
20130
20140
20150
20160
20170
Total76