|
| year | production | consumption |
| 1984 | | 2.19 |
| 1985 | | 2.29 |
| 1986 | | 2.43 |
| 1987 | | 2.73 |
| 1988 | | 2.91 |
| 1989 | | 2.90 |
| 1990 | | 3.11 |
| 1991 | | 3.22 |
| 1992 | | 3.11 |
| 1993 | | 3.11 |
| 1994 | | 3.17 |
| 1995 | | 3.15 |
| 1996 | | 3.60 |
| 1997 | | 3.13 |
| 1998 | | 3.28 |
| 1999 | | 3.36 |
| 2000 | | 3.30 |
| 2001 | | 3.34 |
| 2002 | | 3.36 |
| 2003 | | 3.35 |
| 2004 | | 3.44 |
| 2005 | | 3.45 |
| 2006 | | 3.73 |
| 2007 | | 3.70 |
| 2008 | | 3.51 |
| 2009 | | 3.64 |
| 2010 | | 3.38 |
|
|