|
| year | consumption | change |
| 1984 | | NA |
| 1985 | | NA |
| 1986 | 19.01 | NA |
| 1987 | 21.91 | 15.22 % |
| 1988 | 21.90 | -0.03 % |
| 1989 | 17.79 | -18.77 % |
| 1990 | 16.33 | -8.22 % |
| 1991 | 15.13 | -7.34 % |
| 1992 | 6.92 | -54.29 % |
| 1993 | 14.92 | 115.75 % |
| 1994 | 13.40 | -10.19 % |
| 1995 | 13.95 | 4.11 % |
| 1996 | 13.94 | -0.05 % |
| 1997 | 13.68 | -1.90 % |
| 1998 | 13.72 | 0.29 % |
| 1999 | 13.96 | 1.73 % |
| 2000 | 14.07 | 0.79 % |
| 2001 | 15.33 | 9.01 % |
| 2002 | 17.85 | 16.44 % |
| 2003 | 17.85 | 0.00 % |
| 2004 | 6.84 | -61.67 % |
| 2005 | 7.45 | 8.94 % |
| 2006 | 1.76 | -76.42 % |
| 2007 | 1.19 | -32.53 % |
| 2008 | .97 | -17.86 % |
| 2009 | 1.52 | 56.52 % |
| 2010 | 1.42 | -6.94 % |
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