*Excludes Observations that spanned multiple years

Pre 197011
19700
19710
19720
19730
19740
19750
19760
19770
19780
19791
19800
19810
19820
19831
19840
19850
19863
19873
19884
19890
19900
19911
19921
19932
19940
19951
19960
19970
19980
19990
20000
20016
20020
20030
20042
20050
20061
20070
20081
20090
20100
20110
20120
20130
20140
20150
20161
20170
20180
20190
Total39