*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19800
19810
19820
19830
19840
19850
198614
19870
19880
19890
19901
19911
19922
19930
19940
19951
19960
19970
19980
19992
20000
20018
20023
20039
200450
20052
20060
20070
20080
20090
20100
20110
20120
20130
20140
20150
20161
20170
Total94