There are more than 900 different manuscripts that have been found in Qumran. Almost all are very fragmentary. Of the 900, more than 200 are manuscripts of the Hebrew Bible, so obviously there is more than one copy of many of the texts. The three most popular books are the Book of Psalms, the Book of Deuteronomy and the Book of Isaiah.
39 copies of the Book of Psalms have been found among the Dead Sea Scrolls
36 copies of the Book of Deuteronomy
22 copies of Isaiah.
Interestingly, these are the three most frequently quoted books in the New Testament; the most important books to the Qumran