*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19791
19800
19810
19820
19830
19840
19850
19860
19870
19889
19892
19902
19910
19920
19931
19940
19951
19960
19970
19980
19990
20000
20012
20022
20034
200414
20055
20061
200728
20086
200931
201011
20119
201212
20131
20141
20150
20160
20170
Total143