*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19800
19810
19820
19830
19844
19850
19860
19872
19887
19891
19904
19911
19921
19935
19946
19954
19966
199716
199824
199910
20002
20013
20022
20035
20043
20050
20060
20070
20083
200912
20100
20110
20120
20130
20140
20150
20162
20170
Total123