Sanitary and storm sewers were also on a steady ageing trend in Quebec since the early 1980s. The age grew from an average of 13.7 in 1980 to 18.1 in 2007, slightly above the national average of 17.9 years. As a percentage of estimated useful life, Quebec tracked closely to the national average which has been growing also in most years. In 2007, the provincial rate was 54%, slightly above the national rate of 53%.