*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19800
19810
19820
19830
19840
19851
19862
19877
198820
19896
19905
199112
199211
19932
19947
199512
199616
199711
199819
19990
20009
200112
20020
200315
20043
20054
20062
20073
20081
20092
20100
20110
20122
20130
20140
20150
20160
20170
Total184