|
| year | production | consumption |
| 1984 | | |
| 1985 | | |
| 1986 | | 1.10 |
| 1987 | | 2.01 |
| 1988 | | 1.99 |
| 1989 | | 3.09 |
| 1990 | | 2.54 |
| 1991 | | 2.87 |
| 1992 | | 1.56 |
| 1993 | | 1.44 |
| 1994 | | 1.50 |
| 1995 | | 1.50 |
| 1996 | | 1.54 |
| 1997 | | 1.59 |
| 1998 | | 1.59 |
| 1999 | | 2.34 |
| 2000 | | 2.98 |
| 2001 | | 2.17 |
| 2002 | | 3.18 |
| 2003 | | 4.53 |
| 2004 | | 4.75 |
| 2005 | | 4.63 |
| 2006 | | 4.02 |
| 2007 | | 4.04 |
| 2008 | | 4.16 |
| 2009 | | 4.28 |
| 2010 | | 4.42 |
|
|