Show data table
| 1981 | 19.9% | 1997 | 20.5% | 2013 | 21% |
| 1982 | 16.3% | 1998 | 16.7% | 2014 | 20.8% |
| 1983 | 14.4% | 1999 | 17.8% | 2015 | 18.6% |
| 1984 | 14.2% | 2000 | 16.9% | 2016 | 22.6% |
| 1985 | 15.5% | 2001 | 13.4% | 2017 | 22.9% |
| 1986 | 14.4% | 2002 | 13.7% | 2018 | 20.7% |
| 1987 | 14.8% | 2003 | 16.4% | 2019 | 20.4% |
| 1988 | 15% | 2004 | 17.9% | 2020 | 20.7% |
| 1989 | 15% | 2005 | 17.2% | 2021 | 23.7% |
| 1990 | 14.5% | 2006 | 18.8% | 2022 | 21.7% |
| 1991 | 15.9% | 2007 | 21.3% | 2023 | 18.1% |
| 1992 | 16.2% | 2008 | 18.9% | 2024 | 17.4% |
| 1993 | 17.3% | 2009 | 18.8% | 2025 | 18.5% |
| 1994 | 16.4% | 2010 | 20.7% | 2026 | 17.7% |
| 1995 | 15.8% | 2011 | 22.4% | | |
| 1996 | 16.4% | 2012 | 21.4% | | |
Show data table
| 1981 | 35.8B | 1997 | 281B | 2013 | 455B |
| 1982 | 32.3B | 1998 | 216B | 2014 | 479B |
| 1983 | 32.8B | 1999 | 233B | 2015 | 450B |
| 1984 | 38.5B | 2000 | 225B | 2016 | 573B |
| 1985 | 43.7B | 2001 | 176B | 2017 | 620B |
| 1986 | 48.6B | 2002 | 177B | 2018 | 600B |
| 1987 | 60.9B | 2003 | 207B | 2019 | 591B |
| 1988 | 72.7B | 2004 | 238B | 2020 | 564B |
| 1989 | 82.4B | 2005 | 247B | 2021 | 694B |
| 1990 | 89.5B | 2006 | 288B | 2022 | 622B |
| 1991 | 115B | 2007 | 358B | 2023 | 549B |
| 1992 | 135B | 2008 | 317B | 2024 | 565B |
| 1993 | 167B | 2009 | 318B | 2025 | 627B |
| 1994 | 175B | 2010 | 376B | 2026 | 634B |
| 1995 | 180B | 2011 | 438B | | |
| 1996 | 208B | 2012 | 442B | | |
Show data table
| 1981 | 17.1% | 1997 | 14.1% | 2013 | 20% |
| 1982 | 16.7% | 1998 | 18.5% | 2014 | 17.3% |
| 1983 | 15.5% | 1999 | 17.1% | 2015 | 18% |
| 1984 | 13.3% | 2000 | 17.5% | 2016 | 18.3% |
| 1985 | 14.5% | 2001 | 18.2% | 2017 | 17.4% |
| 1986 | 12.7% | 2002 | 18.5% | 2018 | 18.4% |
| 1987 | 11.8% | 2003 | 19.6% | 2019 | 20.9% |
| 1988 | 11.7% | 2004 | 18.2% | 2020 | 29.9% |
| 1989 | 13% | 2005 | 16.2% | 2021 | 23.7% |
| 1990 | 13.8% | 2006 | 14.8% | 2022 | 28.3% |
| 1991 | 12.8% | 2007 | 13.9% | 2023 | 23.7% |
| 1992 | 13.5% | 2008 | 18.6% | 2024 | 23.2% |
| 1993 | 15.3% | 2009 | 17.3% | 2025 | 23.2% |
| 1994 | 15.4% | 2010 | 16.6% | 2026 | 22.9% |
| 1995 | 16.1% | 2011 | 18.6% | | |
| 1996 | 14.4% | 2012 | 18.3% | | |
Show data table
| 1981 | 30.8B | 1997 | 194B | 2013 | 434B |
| 1982 | 33.1B | 1998 | 239B | 2014 | 396B |
| 1983 | 35.3B | 1999 | 223B | 2015 | 436B |
| 1984 | 36.1B | 2000 | 233B | 2016 | 462B |
| 1985 | 40.8B | 2001 | 239B | 2017 | 471B |
| 1986 | 42.7B | 2002 | 239B | 2018 | 532B |
| 1987 | 48.4B | 2003 | 247B | 2019 | 608B |
| 1988 | 56.6B | 2004 | 242B | 2020 | 816B |
| 1989 | 71.4B | 2005 | 233B | 2021 | 693B |
| 1990 | 85.6B | 2006 | 227B | 2022 | 810B |
| 1991 | 92.2B | 2007 | 235B | 2023 | 721B |
| 1992 | 113B | 2008 | 312B | 2024 | 753B |
| 1993 | 147B | 2009 | 293B | 2025 | 789B |
| 1994 | 164B | 2010 | 301B | 2026 | 818B |
| 1995 | 183B | 2011 | 364B | | |
| 1996 | 183B | 2012 | 377B | | |