*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19756
19760
19770
19780
19790
19800
19810
19820
19830
19840
19850
19860
19870
19880
19890
19905
19911
19921
19932
19941
19952
19961
19973
19982
19991
20002
20015
20020
20030
20044
20056
20061
20070
20082
20090
20100
20116
20122
201311
20140
20150
20160
20170
Total64