*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
19880
19890
19900
19911
19922
19930
19942
19950
19960
19970
19980
19990
20001
20012
20020
20032
20041
20052
20064
200720
200811
20093
20103
20110
20120
20131
20140
20150
20160
20170
Total55