*Excludes Observations that spanned multiple years

Pre 197013
19700
19711
197238
197315
19741
19751
19761
19770
19781
19790
19802
19811
19821
19834
19843
19851
198677
198730
1988479
1989380
199018
199171
199260
1993100
199459
1995154
1996122
1997132
199843
199937
200041
200155
200226
2003116
2004189
2005200
2006124
2007151
2008140
2009152
2010179
2011138
2012120
2013115
2014139
2015125
2016147
2017122
20180
Total4124