A unique form of civil township in Michigan is the charter township, a status created by act of the state legislature in 1947, which grants additional powers and streamlined administration of townships. Charter townships that meet certain criteria are also provided greater protection against annexation by a city or village. Townships must have at least 2,000 residents before they can seek charter status. The means by which a charter is approved affects a charter township's taxing ability. If township voters approve the charter status, the township may levy up to 5 mills without voter approval. If the charter status is approved by the township board alone, the township board may not levy any millage beyond that allowed for general law townships without voter approval. As of April 2001, there were 127 charter townships in Michigan.