*Excludes Observations that spanned multiple years

  B
b
t
W
w
 
Pre 1970000000
1970000000
1971000000
1972000000
1973000000
1974000000
1975000000
1976000000
1977000000
1978000000
1979000000
1980000000
1981000000
1982000000
1983000000
1984000101
1985000000
1986000000
1987000000
1988000101
1989000000
1990000000
1991000000
1992000000
1993000505
1994000606
1995000808
1996000909
1997100809
1998000404
1999100405
2000000303
2001000404
2002000707
2003000707
2004000404
2005200406
2006000101
2007000202
2008000505
200900011011
201000013013
201100019019
2012000303
2013100203
2014000606
2015000404
2016000000
2017000000
2018000000
Total5001410146