*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19800
19811
19820
19831
19840
19851
19860
19870
19883
19897
199011
199111
19924
199314
19943
19954
19969
199729
199812
19994
200017
20010
20023
20030
20048
20053
20061
20070
20081
20090
20100
20110
20120
20130
20149
20152
20162
20173
20180
Total163