*Excludes Observations that spanned multiple years

Pre 19701
19700
19710
19720
19730
19740
19750
19761
19770
19780
19790
19800
19810
19820
19830
19840
19850
19860
19870
19881
19890
19903
19912
19925
19937
19940
19957
19966
199711
19981
19990
20000
20012
20023
20030
20040
20050
20061
20070
20082
20090
20100
20110
20120
20130
20140
20150
20160
20170
Total53