|
| year | consumption | change |
| 1980 | .32 | NA |
| 1981 | .31 | -3.46 % |
| 1982 | .31 | -1.06 % |
| 1983 | .30 | -2.81 % |
| 1984 | .31 | 2.56 % |
| 1985 | .31 | 2.06 % |
| 1986 | .34 | 8.03 % |
| 1987 | .34 | 0.24 % |
| 1988 | .33 | -1.74 % |
| 1989 | .35 | 3.91 % |
| 1990 | .37 | 5.94 % |
| 1991 | .38 | 4.62 % |
| 1992 | .39 | 1.85 % |
| 1993 | .40 | 2.94 % |
| 1994 | .42 | 4.83 % |
| 1995 | .43 | 2.24 % |
| 1996 | .46 | 6.18 % |
| 1997 | .49 | 6.47 % |
| 1998 | .53 | 8.63 % |
| 1999 | .56 | 6.42 % |
| 2000 | .60 | 6.27 % |
| 2001 | .63 | 4.69 % |
| 2002 | .62 | -0.63 % |
| 2003 | .62 | -0.86 % |
| 2004 | .64 | 4.07 % |
| 2005 | .66 | 3.08 % |
| 2006 | .70 | 5.81 % |
| 2007 | .70 | 0.04 % |
| 2008 | .69 | -1.39 % |
| 2009 | .62 | -10.42 % |
| 2010 | .63 | 1.15 % |
|
|