In the 2008 DXCC Yearbook (just came out) it says that about one third of the DXCC applications had at least some LoTW QSLs. Note the LoTW and e-QSL serve different purposes. LoTW is good for WAS and DXCC. e-QSL is not. e-QSL lets you print a card for display. LoTW does not. e-QSL is good for some CQ Magazine awards. LoTW is not.