How many volumes of death note are there? (in the anime not the manga)

OK, so my bro usd 2 watch death note nd he is the 1 who got me in2 it he gav me all of his discs but there were only 8 volumes i finished watching all of them nd i was kinda pissed cuz it just abruptly ended in volume 8 im sure there r thêm but exactly how many? thanks 4 ur help nd ur answers