Year | Value | 2021 | 23.331565549427 | 2020 | 23.777047093763 | 2019 | 24.222528638099 | 2018 | 24.668010182435 | 2017 | 25.113491726771 | 2016 | 25.558973271107 | 2015 | 26.004454815443 | 2014 | 26.449936359779 | 2013 | 26.895417904115 | 2012 | 27.340899448451 | 2011 | 27.786380992787 | 2010 | 28.231862537124 | 2009 | 28.677344081459 | 2008 | 29.122825625795 | 2007 | 29.568307170132 | 2006 | 30.013788714467 | 2005 | 30.459270258804 | 2004 | 30.90475180314 | 2003 | 31.350233347476 | 2002 | 31.795714891812 | 2001 | 32.241196436148 | 2000 | 32.686677980484 | 1999 | 33.13215952482 | 1998 | 33.577641069156 | 1997 | 34.023122613492 | 1996 | 34.468604157828 | 1995 | 34.914085702164 | 1994 | 35.3595672465 | 1993 | 35.805048790836 | 1992 | 36.250530335172 | 1991 | 36.696011879508 | 1990 | 37.141493423844 |
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