I will reply tomorrow if I can remember till then you can read what Charlie Munger (Berkshire Hathway's VP) has to say on this
http://www.gsb.stanford.edu/sites/default/files/38_Munger_0.... ( Page 3)
and check out Alice Schroeder's comments
https://www.youtube.com/watch?v=PnTm2F6kiRQ&feature=youtu.be...