*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19800
19810
19820
19833
19840
19852
19860
19878
19880
19890
19900
19911
19923
19932
19942
19950
19960
19970
199813
19991
20001
20014
20021
20030
20040
200512
20060
20070
20081
20090
20100
20110
20120
20130
20140
20150
20160
20170
Total54