*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19800
19810
19820
19831
19840
19851
19862
19870
19883
19890
19900
19910
19921
19936
19940
19950
19960
19971
19982
19990
20000
20011
20020
20030
20043
20050
20061
20070
20089
20090
20100
20110
20120
20130
20140
20150
20163
20170
Total34