According to the Huffington Post:
The 2010 return lists foreign tax payments Romney made dating back to 2000. By Romney standards, the payments were modest through 2004, averaging $37,000 a year. In 2005, however, his foreign tax bill shot up to $333,149 and stayed high for the next three years, before dipping in 2009, as the financial crisis hit hard.
In 2010, Romney's foreign tax bill was down to $67,173 on declared foreign income of $1,525,982. That's a 4.4 percent rate. After expenses and various other deductions, Romney declared a net foreign income of $392,000, making his net tax rate 17 percent.
Because the presumptive GOP presidential nominee has so far declined to release his earlier tax returns, HuffPost made a rough calculation of his prior foreign earnings by assuming he paid similar tax rates in previous years.It's becoming more and more clear why he doesn't want to give the public any more information than he has to, if this is any indication, he might be better off taking the hit politically.
Using that analysis, paying $333,000 in taxes would translate into gross foreign income of $7.5 million in 2005, or net income of $1.9 million. Even using the much-reduced net income figure, Romney would have earned $7 million in foreign income from 2005 to 2010.