Read this: The reefs at Funafuti have suffered damage, with 80 per cent of the coral becoming bleached as a consequence of the increase in ocean temperatures and ocean acidification. The coral bleaching, which includes staghorn corals, is attributed to the increase in water temperature that occurred during the El Niños that occurred from 1998–2000 and from 2000–2001. A reef restoration project has investigated reef restoration techniques; and researchers from Japan have investigated rebuilding the coral reefs through the introduction of foraminifera. The project of the Japan International Cooperation Agency is designed to increase the resilience of the Tuvalu coast against sea level rise through ecosystem rehabilitation and regeneration and through support for sand production.

What percentage of the Tuvalu coral has become bleached?
What is the answer? (If it cannot be answered, return "unanswerable")
80 per cent