Year % (national estimate) 1960 42.9 1971 40.01 1978 44.54 1981 49.38 1986 43.88 1991 47.03 2001 49.25 2014 36.501 2017 39.291 2018 40.659 2019 39.283 2020 41.895 2021 38.247 2022 37.632