A new study by the U.S. Census Bureau reveals that the city is home to an aging population. The ACS survey, the largest of its kind, is a comprehensive look at America's community demographics. The data covers the years from 2016 through 2020, making it possible to compare the city's population to the same period five years ago. It is the only comprehensive study of American communities that gives detailed data for even the smallest geographic areas.
The population of the city is estimated to be 327,935 in 2007. This includes 452 986 people who live in rental units and 327,995 residents who own their homes. Those in the rental market account for the majority of the population. In addition to renters, San Francisco has a large number of student housing units. The median age of the city is 38.5 years. The city's population is evenly divided between males and females, with approximately four people per 100 people being older than forty.
The city has more than 50 hills within its city limits. Some neighborhoods were named after the hills. Mount Davidson, at 928 feet (283 m) high, is the city's highest point and is capped with a 103-foot cross. Another landmark in the city is the Sutro Tower, a large red television transmission tower. Aside from the mountains and hills, the city is home to some of the world's most famous businesses.