*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19800
19810
19820
19830
19840
19850
198612
198725
19885
19890
19901
19912
19926
19930
19940
19955
19960
19973
19981
19995
20004
20010
20022
20030
20040
20050
20060
20071
20081
20090
20100
20110
20120
20131
20140
20150
20160
20171
20180
20190
20200
Total75