 The population of Angers is relatively young, with 48% of the population being younger than 30 and the proportion of residents over 60 years old (18.9%) being lower than both the national (22.1%) and departmental (21.4%) rates.This is partially explained by the presence of two universities, 21.3% of the population being pupils and students in 2009.The early prosperity of the town was largely due to the nearby quarries of slate, whose abundant use for the roofs of Angers led to its sobriquet as the "Black City".