*Excludes Observations that spanned multiple years

Pre 1970180
197010
19711
19721
19730
19740
197513
19764
19771
19782
19791
19804
19812
19820
19830
19842
19851
19860
19871
19880
19890
19900
19910
199210
199312
19948
19951
19961
19970
19983
19994
20001
20010
20027
20030
20041
200537
200668
20073
200813
200953
201034
20114
20126
20136
20142
20150
20160
20170
Total497