The 6% figure that Jim cited goes back to Carly Fiorina's attempt to 
discredit Hillary in 2013.  I'm not sure who actually started this bit 
of slime, but Fiorina certainly attempted to profit from it.  A number 
of charity watch organizations have checked it out and concluded that 
the attempt to discredit Hillary was based on confusing how private 
foundations and public charities work.  Private foundations operate by 
donating funds to other charitable institutions.  There is a specific 
line in the 990 that identifies those donations and for the Clinton 
Foundation, that was indeed only about 6%.  But, the Clinton Foundation 
is a public charity which engages directly in charitable work, so the 
money would appear under program service expenses and accounts for about 
89% of the total funds.  However, there are additional expenses in 
running a large charity including salaries paid to staff, fundraising 
activities, and a whole raft of administrative expenses.  For the 
Clinton Foundation to not only engage directly in charitable work and to 
keep these costs to less than 11% is pretty amazing.  Most public 
charities wish that they could do as well.
One of the things that helps to keep the administrative costs down is 
that the Clintons do not receive any compensation for their work.  So, 
no, the Clintons are not making 3 million a year.