Considerable improvement in the treatment of HIV has also decreased premature deaths for black men, who were hammered by the epidemic. An estimated 42% of the 1.1m Americans living with HIV today are black, triple their share of the population. At the peak of the epidemic, around 1994, the virus was killing blacks at an age-adjusted rate of nearly 60 per 100,000-or three times the rate at which opioid overdoses killed whites in 2017.
Is the subject of "triple their share of the population" black people? and 42% is the result of being "tripled"? and what does "the population" in their share of the population refer to? Is it Americans as a whole?
Can anyone help me with this sentence?