*Excludes Observations that spanned multiple years

Pre 19700
19700
19711
19722
19730
19742
19751
19760
19770
19780
19791
19800
19810
19820
19830
19840
19850
19860
19870
19880
19890
19901
19910
19921
19930
19940
19950
19960
19974
19980
19992
20000
20010
20020
20031
20040
20050
20060
20073
20080
20090
20100
20110
20120
20130
20140
20150
20160
20170
Total19