*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19801
19810
19820
19830
19840
19850
19860
19870
19882
19894
199011
199120
19928
199340
199412
199510
199612
199710
19983
19993
20002
200117
20026
20033
200423
200512
20065
20075
20089
20091
20103
20113
20120
20130
20140
20150
20163
20170
Total228