|
| year | production | consumption |
| 1980 | | 12.00 |
| 1981 | | 12.00 |
| 1982 | | 14.00 |
| 1983 | | 14.00 |
| 1984 | | 15.00 |
| 1985 | | 16.45 |
| 1986 | | 16.55 |
| 1987 | | 16.83 |
| 1988 | | 17.28 |
| 1989 | | 16.72 |
| 1990 | | 15.80 |
| 1991 | | 14.69 |
| 1992 | | 13.28 |
| 1993 | | 12.82 |
| 1994 | | 13.10 |
| 1995 | | 11.48 |
| 1996 | | 11.86 |
| 1997 | | 7.99 |
| 1998 | .12 | 8.49 |
| 1999 | .20 | 8.66 |
| 2000 | .18 | 8.50 |
| 2001 | .20 | 9.86 |
| 2002 | .38 | 10.67 |
| 2003 | .50 | 10.35 |
| 2004 | .59 | 12.28 |
| 2005 | .55 | 12.63 |
| 2006 | 1.03 | 13.88 |
| 2007 | 2.33 | 15.38 |
| 2008 | 3.21 | 18.16 |
| 2009 | 5.12 | 16.53 |
| 2010 | 5.98 | 17.36 |
| 2011 | 6.98 | 19.00 |
|
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