*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19731
19740
19759
19760
19770
19780
19790
19800
19810
19820
19830
19840
19850
19860
19870
19880
19890
199021
199112
199236
19937
199420
199525
199624
199721
19988
199921
200038
200125
200218
200345
200455
200543
200629
200738
200860
200917
201018
201114
201227
201312
20140
20150
20160
20170
Total644