*Excludes Observations that spanned multiple years

  B
b
t
W
w
 
Pre 1970000000
1970001001
1971000000
1972000000
1973000000
1974000000
1975000000
1976000000
1977000000
1978000000
1979000000
1980001001
1981001001
1982001001
1983001001
1984010001
1985001001
1986000000
1987000000
1988001001
1989001001
1990000000
1991000000
1992000000
1993020002
1994331007
1995011002
1996121004
19970910010
1998000000
199901000010
200001010011
200101210013
200201720019
200301340017
200403800038
2005041005
20060840012
200701820020
20080820010
2009014005
20100660012
2011005005
2012032005
20130380011
201410140015
2015009009
2016000000
2017000000
Total51697700251