*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19791
19800
19810
19820
19830
19840
19850
19860
19870
19880
19890
19900
19910
19920
19930
19942
19950
19961
19970
19980
19992
20001
20010
20024
20036
200411
20051
200618
20071
20080
20091
20100
20110
20120
20130
20140
20150
20160
20170
Total49