|
| year | production | consumption |
| 1984 | | |
| 1985 | | |
| 1986 | 2.08 | 2.08 |
| 1987 | 2.49 | 3.15 |
| 1988 | 2.14 | 2.44 |
| 1989 | 2.29 | 2.83 |
| 1990 | 1.72 | 2.65 |
| 1991 | 2.27 | 2.10 |
| 1992 | 2.56 | 2.46 |
| 1993 | 2.38 | 2.52 |
| 1994 | 2.43 | 2.62 |
| 1995 | 2.43 | 2.57 |
| 1996 | 2.45 | 2.61 |
| 1997 | 2.48 | 2.64 |
| 1998 | 2.48 | 2.66 |
| 1999 | 2.57 | 2.76 |
| 2000 | | 2.84 |
| 2001 | | 3.34 |
| 2002 | | 3.83 |
| 2003 | | 4.11 |
| 2004 | | 4.40 |
| 2005 | | 4.72 |
| 2006 | | 5.00 |
| 2007 | | 5.35 |
| 2008 | | 5.80 |
| 2009 | | 6.12 |
| 2010 | | 5.73 |
|
|