import of cars. Wide-scale development has been made possible by the unhindered movement of goods into Gaza through the Kerem Shalom Crossing and tunnels between the Gaza Strip and Egypt. The current rate of trucks entering Gaza through Kerem Shalom is 250 trucks per day. This figure fluctuates depending on the level of interference with goods being brought into Gaza from Egypt through tunnels. The increase in building activity has led to a shortage of construction workers. To make up for the deficit, young people are being sent to learn the trade in Turkey. Currency Under the Protocol on Economic Relations, the Palestinians are not allowed to independently introduce a separate Palestinian currency. Instead, the Israeli new shekel is the main currency of the Palestinian territories. In the West Bank the Jordanian dinar is also used. The shekel is used for most transactions, especially retail, while the dinar is used more for savings and durable goods transactions. The United States dollar is also sometimes used for savings and for purchasing foreign goods. The dollar is used by the overwhelming majority of transactions overseen by the Palestinian Monetary Authority (that functions as Palestine's central bank), which only represent a fraction of the transactions conducted in Palestine or by Palestinians. In the Gaza Strip, the shekel is also the main currency, though it is in short supply due to the blockade of the Gaza Strip by the PA, Israel and Egypt. Because the Palestinian Monetary Authority does not issue its own currency, it is therefore unable to pursue an independent and effective monetary policy. At the same time, the use of multiple currencies increases the costs and creates inconvenience arising from fluctuating exchange rates. Taxation Taxation in the Palestinian territories is a complex system which may involve payment to the Palestinian Authority (PA) and/or Israel. In 2005 the PA collected approximately $34 million per month from taxes and other charges, while Israel collected about $75 million per month in tariffs on foreign imports and value added taxes (VAT) on Israeli goods and services and on average retained about $15 million for the payment of water and power bills of Palestinians, while forwarding the other $60 million to the PA. Israeli collected funds account for about two-thirds of the PA's self-generated revenue, which Reuters put at $100 million in December 2012. Since the 2006 Palestinian legislative election and the formation of a Hamas