How much virgin forest/wilderness is left in the world that we could protect?

Currently, 2.8% of the Earth's land surface is still intact, and of course our goal is to preserve these areas. As far as rainforests are concerned, there are still 67,149,825 hectares of virgin forest in Peru, at least. According to our current concept, we would need €671,498,250,000 for permanent protection. In British Columbia, Canada, there are still 22.6 million hectares of virgin forest – here we would need €226 billion in donations. Unfortunately, we do not currently know what proportion of these areas are registered in the land registry and are actually available for purchase.