The Guardian US expects to hit $44 million in voluntary reader donations in the U.S. and Canada this year, up 33 percent over last year [..].

  These contributions account for more than 60 percent of the American operation’s total revenue, which last year exceeded costs by $16 million

  (the rest of its revenue comes from advertising and philanthropic support from foundations).

By my reckoning "more than 60 percent of the American operation’s total revenue" + "the rest of its revenue comes from" adds up to 100 percent.

Can you expand on what it is that you feel is not accounted for?