*Excludes Observations that spanned multiple years

Pre 197016
19700
19710
19720
19730
19741
19750
19760
19771
19781
19790
19802
19810
19820
19830
19842
19850
19860
19870
19881
19890
19900
19910
19921
19930
19940
19950
19960
19970
19980
19991
20000
20010
20021
20030
20040
20051
20061
20070
20081
20092
201012
201111
20120
20132
20140
20150
20160
20170
20180
Total57