Season 1 PBS , 2002 Season 2 PBS , 2003 Season 3 PBS , 2004 Season 4 PBS , 2005 Season 5 PBS , 2006 - 2007 Season 6 PBS , 2007 - 2008 Season 7 PBS , 2009 Season 8 PBS , 2010 Season 9 PBS , 2013 - 2014 Season 10 PBS , 2015 Season 11 PBS , 2017 - 2018 Season 12 PBS , 2019 - 2020 Season 13 PBS , 2022 Season 14 PBS , 2023 Season 15 PBS , 2024