Revenue is broken down in the fourth paragraph of the article.
That does not seem to account for all their revenue, it does not say what percentage of all revenue comes from tax money.
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).
Can you expand on what it is that you feel is not accounted for?
… Wait, what makes you think the Guardian is government funded? Which government?