Real estate is the collective term for land, with or without buildings or housing on it, along with other natural resources and immovable properties of similar nature. Usually, this refers to buildings or housing, both for commercial and residential purposes. The business conducted in this sector in New York, can be by individual real estate brokers or realtors, or by agencies that employ them. These professionals help facilitate the process of buying and selling land and property, with or without buildings. The sector is governed by its own set of laws and regulations. The agencies can offer various kinds of services, such as appraisal of value of property, brokerages who help process a transaction between two parties, land development, leasing, property management, relocation services, and real estate marketing. Real estate can also be bought for investment purposes. The professional can be specialized in thse services, and further in commercial, industrial or residential properties. The total value of real estate of developed economies was estimated by The Economist to be at $115 trillion in 2002. This includes stocks and bonds as well. Realtors and real estate agencies in New Yorkoften have a list of available properties for both buying and selling, and the customer can choose, depending on the needs and budget (or the asking price).