Historically, Aden would import goods from the African coast and from Europe, the United States, and India. As of 1920, the British described it as "the chief emporium of Arabian trade, receiving the small quantities of native produce, and supplying the modest wants of the interior and of most of the smaller Arabian ports." At the docks, the city provided coal to passing ships. The only item being produced by the city, as of 1920, was salt. Also, the port was the stop ships had to take when entering the Bab-el-Mandeb; this was how cities like Mecca had received goods by ship. Yemen Airlines, the national airline of South Yemen, had its head office in Aden. On 15 May 1996, Yemen Airlines merged with Yemenia.