*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19781
19790
19801
19811
19820
19830
19840
19850
19864
19871
19889
19895
199013
199122
199212
199329
19944
199524
199620
199713
19987
19997
200015
20016
20028
20036
20045
20054
20061
20071
200812
20091
20100
20110
20120
20130
20144
20150
20162
20170
Total238