Bert, that would take nearly a lifetime. No restrictions were placed on age of contributions to DT that I know of. And as to my 60 years, that's going to be a judgement call in many cases, since we often don't have any solid evidence. Next, problem, who judges? A rough guide may be just to follow what professional folklorists have collected. But even then where do we put some non-professional collectors, like Ford for his 'Traditional Music in America'? Some biographical notes on Ford make it seem like he tried hard to avoid coming in contact with any professional folklorists.