*Excludes Observations that spanned multiple years

  B
b
t
W
w
 
Pre 1970010012
1970000000
1971000000
1972000000
1973000000
1974000000
1975000000
1976000000
1977001001
1978000000
1979000011
1980000000
1981001012
1982000000
1983000000
1984000000
1985000000
1986000000
1987000000
1988001001
1989000000
1990000000
1991010001
1992002002
1993001001
1994000000
1995002002
1996004015
1997002002
1998003014
1999001012
2000002002
2001100001
2002000000
2003010001
2004000000
2005001001
200601100011
2007012025
2008001012
2009000000
2010004004
2011003003
2012003003
2013001001
2014002002
2015002002
2016012003
2017000000
Total16510967