*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19741
19750
19761
19772
19780
19792
19800
19810
19820
19830
19841
19851
19862
19870
19885
19890
19900
19911
19926
19933
19943
19952
19961
199712
19989
19990
20000
200142
20021
200323
20045
20051
20061
20070
20083
20090
201023
201128
20120
201329
20141
20153
201621
201754
201861
201953
20200
Total401