(C) A minimum of four percent of the natural gas that is exported by vessel is transported on such vessels in each of the 10th and 11th calendar years after the calendar year in which this subsection is enacted. (D) A minimum of six percent of the natural gas that is exported by vessel is transported on such vessels in each of the 12th and 13th calendar years after the calendar year in which this subsection is enacted. (E) A minimum of seven percent of the natural gas that is exported by vessel is transported on such vessels in each of the 14th and 15th calendar years after the calendar year in which this subsection is enacted. (F) A minimum of nine percent of the natural gas that is exported by vessel is transported on such vessels in each of the 16th and 17th calendar years after the calendar year in which this subsection is enacted. (G) A minimum of eleven percent of the natural gas that is exported by vessel is transported on such vessels in each of the 18th and 19th calendar years after the calendar year in which this subsection is enacted. (H) A minimum of thirteen percent of the natural gas that is exported by vessel is transported on such vessels in each of the 20th and 21st calendar years after the calendar year in which this subsection is enacted. (I) A minimum of fifteen percent of the natural gas that is exported by vessel is transported on such vessels in— (i) the 22nd calendar year after the calendar year in which this subsection is enacted