*Excludes Observations that spanned multiple years

Pre 19704
19700
19710
19720
19730
19740
19751
19760
19770
19780
19790
19800
19810
19820
19830
19840
19850
19860
198715
198819
19890
19900
19912
19925
19938
19946
19951
199656
199740
199831
19994
200010
20012
20021
20030
20040
20050
20060
20070
20081
20091
20101
20112
20120
20131
20140
20150
20161
20173
20180
20193
20202
20212
20222
20238
20249
Total241