Year Thousands of Persons 1990-01-01 4.1 1991-01-01 4.1 1992-01-01 3.8 1993-01-01 4.6 1994-01-01 3.5 1995-01-01 3.3 1996-01-01 3.3 1997-01-01 3.4 1998-01-01 3.6 1999-01-01 3.3 2000-01-01 2.9 2001-01-01 3.3 2002-01-01 3.3 2003-01-01 3.2 2004-01-01 3.5 2005-01-01 3.4 2006-01-01 3.5 2007-01-01 3.4 2008-01-01 3.4 2009-01-01 3.4 2010-01-01 3.4 2011-01-01 3.6 2012-01-01 3.4 2013-01-01 3.4 2014-01-01 3.3 2015-01-01 3.3 2016-01-01 3.4 2017-01-01 3.2