Bestand
1971(1972) - 2003(2004); 2004 - 2007
[1971=6,3512; 1972=7,782; 1973=7,2413; 1974=7,3822; 1975=7,5677; 1976=8,713; 1977=8,2017; 1978=8,3116; 1979=8,4129; 1980=9,812; 1981=9,1960; 1982=10,361; 1983=10,2058; 1984=10,3802; 1985=10,6087; 1986=11,922; 1987=11,3069; 1988=11,5450; 1989=11,7628; 1990=12,2113; 1991=12,4068; 1992=12,6225; 1993/94=13,130; 1995=13,2682; 1996=13,5850; 1997=13,8759; 1999=14,2488; 2000=14/5064; 2001=14,8754; 2002=15,265; 2003=15,2456; 2004=15,4609; 2005=16,335; 2006=16,3984; 2007=16,7394 von! Bundestag Drucksache]