2007,0.351,0.396,0.431
2006,0.322,0.37,0.416
2005,0.303,0.35,0.436
2004,0.372,0.414,0.455
2003,0.312,0.352,0.436
2002,0.322,0.388,0.425
2001,0.35,0.381,0.457
2000,0.387,0.46,0.539
1999,0.343,0.412,0.572
1998,0.358,0.414,0.518
1997,0.345,0.414,0.519
1996,0.356,0.422,0.504
1995,0.342,0.432,0.544
1994,0.385,0.445,0.518
1993,0.188,0.212,0.266
1992,0.253,0.284,0.305