|
| year | consumption | change |
| 1980 | 1.90 | NA |
| 1981 | 2.00 | 5.37 % |
| 1982 | 2.25 | 12.16 % |
| 1983 | 2.46 | 9.25 % |
| 1984 | 2.75 | 11.95 % |
| 1985 | 2.79 | 1.41 % |
| 1986 | 2.91 | 4.19 % |
| 1987 | 2.93 | 0.70 % |
| 1988 | 3.03 | 3.65 % |
| 1989 | 3.03 | 0.02 % |
| 1990 | 3.03 | 0.00 % |
| 1991 | 3.12 | 2.74 % |
| 1992 | 3.20 | 2.67 % |
| 1993 | 3.20 | 0.00 % |
| 1994 | 3.28 | 2.60 % |
| 1995 | 10.28 | 213.10 % |
| 1996 | 11.36 | 10.47 % |
| 1997 | 13.30 | 17.08 % |
| 1998 | 15.98 | 20.22 % |
| 1999 | 16.41 | 2.68 % |
| 2000 | 17.46 | 6.36 % |
| 2001 | 20.47 | 17.27 % |
| 2002 | 21.94 | 7.18 % |
| 2003 | 23.74 | 8.19 % |
| 2004 | 26.46 | 11.49 % |
| 2005 | 28.02 | 5.88 % |
| 2006 | 30.97 | 10.55 % |
| 2007 | 33.20 | 7.19 % |
| 2008 | 34.34 | 3.42 % |
| 2009 | 32.30 | -5.94 % |
| 2010 | 26.25 | -18.71 % |
| 2011 | | NA |
|
|