Task: Text Simplification
Input (English): riaa website although total worldwide album sales are not calculated by any single entity , as of 2004 several industry sources estimated rush 's total worldwide album sales at over 40 million units.
Output (English): total worldwide album sales are not calculated by any single entity , however the riaa website mentions that as of 2004 several industry sources estimated rush 's total worldwide album sales at over 40 million units.