Unless I'm mistaken, it's not 1% of the American population that has brain cancer. It's that each individual has less than a 1% chance of developing brain cancer. So, if this figure of less than 1% is in fact on the order of 0.5%, a 60% increase in this figure would take it to 0.8%.
"In 2023, an estimated 24,810 adults (14,280 men and 10,530 women) in the United States will be diagnosed with primary cancerous tumors of the brain and spinal cord." https://www.cancer.net/cancer-types/brain-tumor/statistics#:...
24810 is 0.0074751431153962% of 331900000
60% more than 0.0074751431153962 is
0.01196022898463392
