The official language of Montreal is French as defined by the city's charter. It is among the five largest French-speaking cities in the world. As of the 2006 Canadian Census, 1,620,693 people resided in the city of Montreal proper. The population of the Montreal Census Metropolitan Area (also known as Greater Montreal Area) was 3,635,571 at the same 2006 census. In the census metropolitan area, French is the language most spoken at home by 70.5% of the population (as of 2006 census). In 2007, Forbes Magazine ranked Montreal as the 10th cleanest city in the world. In the June 19th, 2008 edition of London based Monocle Magazine, Montreal was ranked 16th in a list of the world's 25 most liveable cities. Contributing factors included a strong-arts community, booming aerospace industry and a vast network of free wireless internet.