|
| year | production | consumption |
| 1980 | | |
| 1981 | | |
| 1982 | | |
| 1983 | | |
| 1984 | | |
| 1985 | | |
| 1986 | | |
| 1987 | | |
| 1988 | | |
| 1989 | | |
| 1990 | | |
| 1991 | | |
| 1992 | | 19.43 |
| 1993 | | 21.41 |
| 1994 | | 17.94 |
| 1995 | | 18.45 |
| 1996 | | 23.34 |
| 1997 | | 21.07 |
| 1998 | | 22.36 |
| 1999 | | 20.00 |
| 2000 | | 22.07 |
| 2001 | | 18.48 |
| 2002 | | 20.17 |
| 2003 | | 19.80 |
| 2004 | | 19.65 |
| 2005 | | 19.89 |
| 2006 | | 19.63 |
| 2007 | | 20.19 |
| 2008 | | 18.72 |
| 2009 | | 19.10 |
| 2010 | | 18.58 |
| 2011 | | 19.00 |
|
|