|
| year | production | consumption |
| 1984 | | |
| 1985 | | |
| 1986 | 2.67 | 3.78 |
| 1987 | 2.46 | 2.36 |
| 1988 | 2.49 | |
| 1989 | 2.66 | 2.42 |
| 1990 | 3.28 | 2.49 |
| 1991 | 2.82 | 2.28 |
| 1992 | 1.90 | 1.75 |
| 1993 | 2.19 | 1.78 |
| 1994 | 2.29 | 2.35 |
| 1995 | 2.30 | 1.95 |
| 1996 | 2.36 | 1.94 |
| 1997 | 2.35 | 2.10 |
| 1998 | 2.54 | 2.12 |
| 1999 | 3.41 | 2.17 |
| 2000 | 4.13 | 2.17 |
| 2001 | 4.11 | 2.20 |
| 2002 | 4.11 | 8.53 |
| 2003 | 4.29 | 2.16 |
| 2004 | 4.07 | 2.17 |
| 2005 | 4.25 | 2.22 |
| 2006 | 3.21 | 2.19 |
| 2007 | 2.64 | 2.92 |
| 2008 | 2.48 | 2.80 |
| 2009 | 2.18 | 3.17 |
| 2010 | .95 | 2.19 |
|
|
