Greece is a maritime nation by tradition, as shipping is arguably the oldest form of occupation of the Greeks and has been a key element of Greek economic activity since ancient times. Today, shipping is the country's most important industry worth $21.9 billion in 2018. If related businesses are added, the figure jumps to $23.7 billion, employs about 392,000 people (14% of the workforce), and shipping receipts are about 1/3 of the nation's trade deficit. In 2018, the Greek Merchant Navy controlled the world's largest merchant fleet, in terms of tonnage, with a total DWT of 834,649,089 tons and a fleet of 5,626 Greek-owned vessels, according to Lloyd's List. Greece is also ranked in the top for all kinds of ships, including first for tankers and bulk carriers.