*Excludes Observations that spanned multiple years

Pre 19700
19700
19711
19720
19730
19740
19750
19760
19770
19780
19790
19800
19810
19820
19830
19842
19852
19862
19872
198815
198917
19909
199114
199218
199310
19945
199527
199621
199718
199830
19994
200011
20013
20021
20034
20045
20056
20061
20072
20084
20090
20102
20113
20120
20130
20140
20150
20160
20170
Total239