*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19791
19801
19811
19820
19831
19842
19851
19860
19877
19882
19890
19900
19912
19921
19930
19946
19950
19960
19973
19983
19990
20000
20010
20020
20030
20040
20051
20060
20072
20080
20090
20100
20110
20120
20130
20140
20150
20160
20170
Total34