Piracy is a robbery committe at sea, or sometimes on the shore, without a commission from a sovereign nation (robbery with sovereign commission is privateering, and distinct from piracy). Seaborne piracy against transport vessels remains a significant issue (with estimated worldwide losses of US $13 to $16 billion per year), particularly in the waters between the Pacific and Indian Oceans, off the Somali coast, and also in the Strait of Malacca and Singapore, which are used by over 50,000 commercial ships a year. A recent surge in piracy off the Somali coast spurred a multi-national effort led by the United States to patrol the waters near the Horn of Africa to combat piracy. While boats off the coasts of North Africa and the Mediterranean Sea are still assailed by pirates, the Royal Navy and the U.S. Coast Guard have nearly eradicated piracy in U.S. waters and in the Caribbean Sea.