|
| year | production | consumption |
| 1980 | | |
| 1981 | | |
| 1982 | | |
| 1983 | | |
| 1984 | | |
| 1985 | | |
| 1986 | | |
| 1987 | | |
| 1988 | | |
| 1989 | | |
| 1990 | | |
| 1991 | | |
| 1992 | | 52.97 |
| 1993 | | 21.19 |
| 1994 | | 22.60 |
| 1995 | | 26.31 |
| 1996 | | 28.82 |
| 1997 | | 37.43 |
| 1998 | | 56.50 |
| 1999 | | 35.32 |
| 2000 | | 39.55 |
| 2001 | | 44.85 |
| 2002 | | 47.32 |
| 2003 | | 49.79 |
| 2004 | | 50.85 |
| 2005 | | 53.68 |
| 2006 | | 51.95 |
| 2007 | | 34.82 |
| 2008 | | 33.41 |
| 2009 | | 23.06 |
| 2010 | | 24.76 |
| 2011 | | 21.61 |
|
|