Detroit's protracted decline has resulted in severe urban decay and thousands of empty buildings around the city. Some parts of Detroit are so sparsely populated that the city has difficulty providing municipal services. The city has considered various solutions, such as demolishing abandoned homes and buildings; removing street lighting from large portions of the city; and encouraging the small population in certain areas to move to more populated locations. While some have estimated 20,000 stray dogs roam the city, studies have shown the true number to be around 1,000-3,000. Roughly half of the owners of Detroit's 305,000 properties failed to pay their 2011 tax bills, resulting in about $246 million in taxes and fees going uncollected, nearly half of which was due to Detroit; the rest of the money would have been earmarked for Wayne County, Detroit Public Schools, and the library system.