|
| year | production | consumption |
| 1980 | | |
| 1981 | | |
| 1982 | | |
| 1983 | | |
| 1984 | | |
| 1985 | | |
| 1986 | | |
| 1987 | | 10.98 |
| 1988 | | 13.00 |
| 1989 | | 19.03 |
| 1990 | | 23.00 |
| 1991 | | 24.00 |
| 1992 | | 27.37 |
| 1993 | | 30.16 |
| 1994 | | 29.66 |
| 1995 | | 30.02 |
| 1996 | | 31.08 |
| 1997 | | 31.25 |
| 1998 | | 30.41 |
| 1999 | | 30.90 |
| 2000 | | 28.43 |
| 2001 | | 31.08 |
| 2002 | | 31.36 |
| 2003 | | 32.70 |
| 2004 | | 31.47 |
| 2005 | | 29.28 |
| 2006 | | 29.31 |
| 2007 | | 32.53 |
| 2008 | | 27.79 |
| 2009 | | 39.69 |
| 2010 | | 54.03 |
| 2011 | | 46.97 |
|
|