*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19800
19810
19820
19830
19840
19850
19860
19870
19888
19890
19900
19913
19921
19935
19940
19951
19960
19971
19980
19992
20000
200112
20020
20034
200439
20052
20060
20070
20080
20090
20100
20110
20120
20130
20140
20150
20160
20170
Total78