*Excludes Observations that spanned multiple years

Pre 19701
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19800
19810
19821
19830
19840
19850
19860
19870
19880
19890
19900
19910
19922
19933
19942
199538
19966
19971
199815
19992
20002
20010
20021
20033
20040
20050
20060
20070
20086
20090
20108
20116
20120
20130
20140
20150
20160
20170
Total97