Specifies how much each index node should be filled as a
    percentage of its size. You cannot specify this argument in an
    ALTER INDEX statement that refers to a hashed index. The valid
    range is 1 percent to 100 percent. The default is 70 percent.

    Both the PERCENT FILL and USAGE clauses specify how full an index
    node should be initially. You should specify either the PERCENT
    FILL or USAGE clause but not both.