The Trans-Alaska Pipeline produces 5 percent of the U.S.’s oil, but for Alaska, it’s so much more. The pipeline system has produced jobs and revenue for the state and its people since it was completed in 1977.

On June 20, 1977, the Trans-Alaska Pipeline funneled the first batch of oil through its pipes, carrying it from Prudhoe Bay to Valdez. Since then, the Alyeska Pipeline Service Company says the pipeline has moved more than 17.2 billion barrels of oil.

Known as TAPS, the pipeline project began after the discovery of oil in Prudhoe Bay in March of 1968. In 1988, it reached peak production, pumping more than 2 million barrels of oil a day. The highest recorded production day was Jan. 14, with 2.1 million barrels pumped south in a single day, according to Alyeska Pipeline’s website.

While production has ebbed and flowed since then, a steady decline was recorded starting in the early 2000s. The 800-mile long pipeline now moves fewer barrels of oil each day than it did the first year of production.