*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19800
19810
19820
19830
19840
19850
19861
19873
19880
19892
19904
19910
19920
19935
19943
199510
19960
19973
19981
19990
20001
20010
20026
20032
20040
20052
20060
20071
20084
20090
20100
20110
20127
20130
20140
20150
20160
20170
20180
20190
20200
Total55