Season 1 PBS , 2015 Watch now Season 2 PBS , 2015 Watch now Season 3 PBS , 2015 - 2016 Watch now Season 4 PBS , 2016 Watch now Season 5 PBS , 2017 Watch now Season 6 PBS , 2017 Season 7 PBS , 2018 Season 8 PBS , 2018 - 2019 Season 9 PBS , 2019 - 2020 Season 10 PBS , 2020 - 2021 Season 11 PBS , 2021 Season 12 PBS , 2021 Season 13 PBS , 2022