That depends on how you're counting. About 2/3 of star systems have only one star. About 2/3 of stars exist in a system with multiple stars. However, the hig

That depends on how you're counting. About 2/3 of star systems have only one star. About 2/3 of stars exist in a system with multiple stars. However, the higher the mass, the more likely it is to be in a multiple-star system. For stars with a mass high enough to form a black hole ... hm, Wikipedia says "at least 80%" but makes it unclear which statistic is being measured.