*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19741
19750
19760
19770
19780
19790
19800
19810
19820
19830
19840
19850
19860
19870
19880
19890
19906
19912
19923
19930
19941
19951
19961
19971
19982
19991
20001
20011
20021
20036
20040
20050
20063
20070
20080
20090
20100
20111
20122
20131
20142
20151
20165
20175
20180
Total48