*Excludes Observations that spanned multiple years

Pre 19703
19700
19710
19720
19730
19740
19750
19760
19770
19781
19790
19800
19810
19820
19831
19840
19850
19860
19870
19880
19890
19900
19910
19920
19931
19940
19950
19961
19971
19980
19990
20000
20010
20020
2003172
20043
200535
20062
20076
20084
200914
20103
20111
20122
20132
20140
20150
20165
201718
20180
Total275