*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19800
19810
19820
19830
19840
19850
19862
19870
19881
19890
19904
19914
19921
19930
19943
19956
19960
19970
19980
19990
20000
20010
2002270
200325
200431
20050
20069
20071
200811
20091
201029
201125
20120
20131
20140
20150
20160
20170
20180
20190
Total424