*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19792
19800
19810
19820
19831
19840
19851
19862
19872
198835
19890
19900
19911
19921
19931
19944
19953
19960
19972
19980
19996
200025
200115
200219
20031
20047
20050
20065
20070
200818
20099
20105
201113
20120
20136
20144
20150
20169
20175
20188
201972
20200
20210
Total282