|
| year | production | consumption |
| 1980 | | |
| 1981 | | |
| 1982 | | |
| 1983 | | |
| 1984 | | |
| 1985 | | 2.89 |
| 1986 | | 3.43 |
| 1987 | | 3.50 |
| 1988 | | 3.65 |
| 1989 | | 3.24 |
| 1990 | | 3.39 |
| 1991 | | 3.85 |
| 1992 | | 3.86 |
| 1993 | | 4.20 |
| 1994 | | 4.56 |
| 1995 | | 4.56 |
| 1996 | | 4.70 |
| 1997 | | 7.60 |
| 1998 | | 7.16 |
| 1999 | | 7.16 |
| 2000 | | 7.48 |
| 2001 | | 7.58 |
| 2002 | | 7.78 |
| 2003 | | 8.05 |
| 2004 | | 8.16 |
| 2005 | | 8.33 |
| 2006 | | 8.45 |
| 2007 | | 9.47 |
| 2008 | | 13.40 |
| 2009 | | 11.64 |
| 2010 | | 11.89 |
| 2011 | | |
|
|