| Vuosi Year |
Määrä (1000 tonnia) Absolute amounts (1000 tonnes) |
Suhde tuotantomäärään, % Proportional to the volume of production, % |
| 1988 | 17.6 | 0.110 |
| 1991 | 16.2 | 0.100 |
| 1992 | 16.0 | 0.110 |
| 1993 | 13.8 | 0.080 |
| 1994 | 13.3 | 0.090 |
| 1995 | 11.3 | 0.060 |
| 1996 | 11.9 | 0.060 |
| 1997 | 11.0 | 0.050 |
| 1998 | 11.5 | 0.050 |
| 1999 | 11.1 | 0.045 |
| 2000 | 11.8 | 0.048 |
| 2001 | 11.4 | 0.048 |
| 2002 | 10.8 | 0.044 |
| 2003 | 9.9 | 0.039 |
| 2004 | 9.8 | 0.037 |
| 2005 | 8.3 | 0.032 |
| 2006 | 8.4 | 0.029 |
| 2007 | 7.8 | 0.026 |
| 2008 | 7.1 | 0.024 |
| 2009 | 8.2 | 0.030 |
| 2010 | 9.9 | 0.036 |
| 2011 | 8.7 | 0.031 |