Americans have splashed out $59 billion more on fuel since President Donald Trump started his war against Iran — and the extra costs have already eaten up this year's average tax refund , according to a report Friday. Moody's chief economist Mark Zandi estimated that the increased spending amounted to about $450 per U.S. household, "made up mostly of gasoline, then there's a diesel cost and an implied jet fuel cost in those higher airline fees,” CNBC senior economics reporter Steve Liesman said on the cable network's Squawk Box show. The added costs were initially offset by this year's increase in the size of many federal income tax refunds, which averaged around $380 more per household, but by mid-May, "the extra fuel cost outstrips the refunds," and "now it's higher," Liesman said, according to a transcript posted on the Mediaite website.…