An American woman grievously injured in the eruption of New Zealand's White Island volcano has died in an Auckland hospital. The death of Atlanta resident Mayuri "Mary" Singh brings the death toll to 19, including two victims who are presumed dead but whose bodies have not been recovered, USA Today reports. A friend tells 11Alive that Singh, who suffered burns over 70% of her body, died Sunday from complications from her treatment, which included skin grafts. Singh's husband, Pratap, remains hospitalized with burns over 40% of his body, the friend says. Singh is the sixth severely burned volcano victim to die from their injuries after the Dec. 9 eruption. Authorities believe the other 13 were killed instantly. (Four days after the eruption, a risky mission recovered six bodies.)