*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19791
19803
19810
19820
19830
19840
19850
198614
19879
198848
19892
19902
19911
199219
19935
19946
199539
19965
199715
19981
19992
20001
20016
200213
20032
20047
20058
20061
20070
20088
20090
201031
201133
20121
20130
20140
20150
20162
20170
Total285