For 100 years, the Panama Canal has been a fundamental part of global shipping. Approximately 5% of all global shipping goes through the canal, and 70% of US imports and exports. Although originally built and operated by the United States, transfer of ownership of the canal to Panama began on September 7, 1977, with the signing of the Panama Canal Treaty (also known as the Torrijos-Carter Treaty) by the two countries. The agreement provided that on December 31, 1999, the US would give all interest in the canal to Panama. The countries also signed the Treaty Concerning the Permanent Neutrality and Operation of the Panama Canal, witnessed by 28 other governments that agreed the canal should always remain “open, safe, neutral and accessible to vessels of all nations.” The canal is now managed by the Panama Canal Authority, a Panamanian government agency established and regulated by the Panama Constitution and specific legislation.