*Excludes Observations that spanned multiple years

  B
b
t
W
w
 
Pre 197000170017
1970000000
1971000000
1972002002
1973001001
1974003003
1975003003
1976001001
1977000000
1978001001
1979003003
1980000000
1981001001
1982001001
1983001001
1984000000
1985005005
1986000000
1987001001
1988002002
1989001001
1990003003
1991001001
1992001001
1993002002
1994002002
1995001001
1996000000
1997000000
1998004004
1999000000
2000000000
2001000000
2002000000
2003001001
2004000000
2005002002
2006000000
2007000000
2008002002
2009000000
2010001001
2011001001
2012001001
2013000000
2014001001
2015000000
2016001001
2017000000
Total00670067