Lying 47 km (29 miles) off the coast of France, Guernsey and its dependencies form the northwestern part of the Channel Islands, historically part of the Duchy of Normandy. English is the language most commonly used, but the Norman patois is spoken in some villages, and French is used in some formalities of the legislature. Travel to France is easier than to the UK; Alderney is only 13 km (8 miles) from the French mainland. Residents on the smaller islands have no need for cars, and life continues in an unhurried manner that has changed little through the centuries. The islanders guard this lifestyle with strict residence laws. Guernsey's mild climate has encouraged the development of tourism and market gardening as major industries. Tomatoes and flowers are produced mainly for the UK market. The low tax system, independent of the UK, has led to a substantial and profitable financial services industry. Many international banks have Guernsey subsidiaries.