*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19751
19760
19770
19780
19790
19801
19810
19820
19832
19840
19850
19860
19871
198831
19895
19906
19917
199213
199312
19948
19952
19960
19970
19982
19992
20000
20019
20020
20032
200440
20050
20061
20071
200815
200911
201014
201113
20120
20130
20141
20150
20164
20170
Total204