*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19800
19810
19820
19830
19840
19850
19860
19873
19883
19893
19900
19912
199210
19935
19947
199545
19961
19974
199829
19996
20007
20015
20021
20031
20047
200519
20060
20072
20089
20093
201030
201138
20120
20131
201410
20150
20167
20170
20180
Total258