State the royalty percentage for the most year to date sale title within the 20000 range.
most year to date sales refers to MAX(ytd_sales); range limit means high range which refers to hirange; the 20000 range refers to hirange<20000
SELECT MAX(T1.ytd_sales) FROM titles AS T1 INNER JOIN roysched AS T2 ON T1.title_id = T2.title_id WHERE T2.lorange > 20000 AND T2.hirange < 20000