*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19801
19811
19820
19830
19840
19850
19860
19870
198829
19891
19900
19912
19924
19936
19949
199510
19968
19977
199816
19994
20003
20018
20021
20035
20045
20051
20060
20070
20081
20091
20101
20115
20128
201312
20145
20151
20168
20170
20188
20190
20200
20210
20220
Total171