The Commonwealth has also come to monopolise income tax. Once the advantages of income tax were recognised, both the Commonwealth and the States levied income taxes. However, during World War II, the Commonwealth government decided to take over the collection of income taxes and return some proceeds to the States as grants. The Commonwealth passed legislation to levy income tax at a nationwide rate similar to the previous combination of Commonwealth tax and the various state taxes. Separate legislation then granted section 96 monetary grants to states if the State did not levy income taxes. In practice, it would be difficult for States to continue taxing.