Economy of Devon (chewing gum) and HMNB Devonport (the largest naval base in western Europe) are in Plymouth. Torquay was home to Beverage Brands, the producers of WKD Original Vodka. Britannia Royal Naval College is at Dartmouth. Mining for tin and copper was carried on in Devon from ancient times until the 1930s: see Dartmoor tin-mining. Agriculture has been an important industry in South West England since the 19th century: approximately 80% of land in the South West of England is in agricultural use (19.6% of England's total). In the later 19th and early 20th centuries there were a number of potteries in
Royal Air Force College Cranwell a roughly circular grass area ("The Orange") toward the parade ground. The building has been used for RAF officer training since HRH the Prince of Wales (later Edward VIII) officially opened it in October 1934. In 1987 the building was given Grade II listed status. The College is the RAF equivalent of the Royal Navy's Britannia Royal Naval College and the British Army's Royal Military Academy Sandhurst. At present, most RAF officer cadets complete a 24-week course within the College's Officer and Aircrew Cadet Training Unit (OACTU), Within OACTU the officer cadets undertake transformational leadership tuition, academic air power studies