|
| year | production | consumption |
| 1984 | | |
| 1985 | | |
| 1986 | 1.10 | 1.19 |
| 1987 | 1.15 | 1.18 |
| 1988 | 1.21 | 1.21 |
| 1989 | 1.31 | 1.31 |
| 1990 | 1.38 | 1.35 |
| 1991 | 1.38 | 1.36 |
| 1992 | 1.38 | 1.38 |
| 1993 | 1.43 | 1.43 |
| 1994 | 1.33 | 1.33 |
| 1995 | 1.13 | 1.27 |
| 1996 | 1.30 | 1.36 |
| 1997 | 1.59 | 1.59 |
| 1998 | | 1.71 |
| 1999 | | 1.71 |
| 2000 | | 1.91 |
| 2001 | | 1.98 |
| 2002 | | 1.98 |
| 2003 | | 1.98 |
| 2004 | | 2.14 |
| 2005 | | 2.20 |
| 2006 | | 2.28 |
| 2007 | | 2.34 |
| 2008 | | 2.28 |
| 2009 | | 2.22 |
| 2010 | | 2.19 |
|
|