*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19751
19760
19770
19780
19790
19800
19810
19820
19830
19840
19850
19860
19870
19880
19890
19903
19914
19928
19933
19943
19951
19961
19971
19983
19996
20004
20015
20022
200310
200410
20055
200616
200719
200829
200910
20107
20114
20127
20132
20140
20150
20160
20170
Total164