housing. There was a 30% increase in the number of apartments in Sydney between 1996 and 2006. Public housing in Sydney is managed by the Government of New South Wales. Suburbs with large concentrations of public housing include Claymore, Macquarie Fields, Waterloo, and Mount Druitt. The Government has announced plans to sell nearly 300 historic public housing properties in the harbourside neighbourhoods of Millers Point, Gloucester Street, and The Rocks. Sydney is one of the most expensive real estate markets globally. It is only second to Hong Kong with the average property costing 14 times the annual Sydney salary as of December 2016. A range of heritage housing styles can be found throughout Sydney. Terrace houses are found in the inner suburbs such as Paddington, The Rocks, Potts Point and Balmain–many of which have been the subject of gentrification. These terraces, particularly those in suburbs such as The Rocks, were historically home to Sydney's miners and labourers. In the present day, terrace houses now make up some of the most valuable real estate in the city. Federation homes, constructed around the time of Federation in 1901, are located in suburbs such as Penshurst, Turramurra, and in Haberfield. Haberfield is known as "The Federation Suburb" due to the extensive number of Federation homes. Workers cottages are found in Surry Hills, Redfern, and Balmain. California bungalows are common in Ashfield, Concord, and Beecroft. Larger modern homes are predominantly found in the outer suburbs, such as Stanhope Gardens, Kellyville Ridge, Bella Vista to the northwest, Bossley Park, Abbotsbury, and Cecil Hills to the west, and Hoxton Park, Harrington Park, and Oran Park to the southwest. Parks and open spaces The Anzac War Memorial in Hyde Park is a public memorial dedicated to the achievement of the Australian Imperial Force of World War I. The Royal Botanic Garden is the most iconic green space in the Sydney region, hosting both scientific and leisure activities. There are 15 separate parks under the administration of the City of Sydney. Parks within the city centre include Hyde Park, The Domain and Prince Alfred Park. The Centennial Parklands is the largest park in the City of Sydney, comprising . The inner suburbs include Centennial Park and Moore Park in the east (both within the City of Sydney local government area), while the outer suburbs contain Sydney Park and Royal National Park in the south, Ku-ring-gai Chase National Park