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The Senate originally had a procedure for ending debate called "moving the previous motion" (copied from the British Parliament). It was eliminated in 1806. From 1806-1917, there was unlimited debate. In 1917, the cloture rule was added with a majority requirement of 2/3 of Senators present. The majority was raised to 2/3 of all Senators in 1949, then changed back to 2/3 of those present in 1959. In 1975, it was lowered to 3/5 of all Senators, but cloture on rule changes was left at 2/3 of those present. In 1979, in order to stop the stall tactics that became known as "post-cloture filibusters", post-cloture debate was limited to 100 hours. It was changed to 30 hours in 1987.