*Excludes Observations that spanned multiple years

Pre 19700
19700
19710
19720
19730
19740
19750
19760
19770
19780
19790
19800
19810
19820
19830
19840
19850
19861
19872
19881
19890
19902
19910
19920
19931
19941
199515
199610
199732
199813
199963
200032
200181
2002124
20031060
2004616
2005356
200665
200731
200880
2009330
2010290
2011130
2012145
2013106
201466
201599
2016118
2017105
201844
Total4019