1980 338.7 1982 341.2 1984 344.4 1986 347.2 1988 351.5 1990 354.2 1992 356.3 1994 358.6 1996 362.4 1998 366.5 2000 369.4 2002 373.2 2004 377.5 2006 381.9 2008 385.6 2010 389.9 2012 393.8