Do the other 30% have no ear wax?
If you want demographics, I've found online that: "dry earwax is very common (80-95 per cent) among East Asians, but is lower (30-50 per cent) in southern Asia, Pacific Islands, Central Asia and Asia Minor, and in Native North Americans and Inuit peoples of Asian ancestry. It's very uncommon among Europeans and Africans (0-3 per cent)". http://www.abc.net.au/science/articles/2015/04/14/4213402.ht...