What percentage of salmon that cross Lower granite survive to Idaho hatcheries? Not counting harvested fish. Just a % number that will survive the journey

Natural mortality (excluding harvest) for salmon between Lower Granite Dam and hatchery facilites varies by facility and year but typically is not more than 5%. So if  there were no harvest in Idaho and 10,000 hatchery fish crossed Lower Granite Dam 9,500 or more would make it back to hatcheries. Some portion of the 5% that do not make it back to hatcheries die or are eaten by predators during their upstream migration and others stray into other streams and spawn naturally.