To call Birmingham the International country code is + 44 (that is, for U.K.) while the area code to be dialed is 121. A city and metropolitan borough, Birmingham is located in the West Midlands, in England. It is the biggest of England's core cities. It is commonly regarded as the UK's second city. Birmingham grew to importance as a manufacturing and engineering hub but currently the service sector dominates its economy. Birmingham is a key financial and administrative centre. Currently tourism too plays an increasingly vital part of the city's local economy. The Birmingham area, with its major facilities like the National Exhibition Centre and the International Convention Centre accounts for 42 percent of conference and exhibition trade in the UK. Birmingham City Centre is the second largest retail centre in the UK, with a turnover of £2.2bn annually.