A group of Tasmanian botanists have claimed that a King's holly shrub, the only one of its species in the world, is also the oldest living plant. Using carbon-14 dating of charcoal found along with fossilized leaf fragments, they arrived at an age of 43, 000 years for the plant, whose exact location in south-west Tasmania is being kept a secret. What percent of the original carbon-14 in the charcoal was present?