Year % 1997 9.413067552602437 1998 12.852552659764378 1999 12.773172569706118 2000 12.754743499648631 2001 13.162257144751674 2002 14.673721340388006 2003 14.141279765864049 2004 15.05111945127476 2005 14.62990561351217 2006 15.330450895614579 2007 16.098807495741056 2008 16.53089973663257 2009 17.492288150970786 2010 17.84536020634635 2011 18.165655079394266 2012 19.495949594959495 2013 20.68114511352419 2014 21.315422633379807 2015 21.604305484367 2016 22.06141684402555 2017 22.60083018400347 2018 23.30505888814305 2019 23.87446403049071 2020 24.605490382897646 2021 24.92982141790599 2022 25.336959806588094 2023 25.73060331733398