Washington, May 18 (IANS): Financial statements of Democratic front-runner Hillary Clinton showed that she earned nearly $7 million last year through sales of her latest book as well as paid speeches.

The campaign team for the former secretary of state on Tuesday disclosed her 2015 financial statements, which show that she received more than $5 million from sales of her book 'Hard Choices' and $1.5 million from paid speeches, EFE news reported.

The documents were filed to the Federal Election Commission, and also reported that her husband and former US president Bill Clinton earned over $5 million from paid speeches last year.

The speeches given in exchange for money have become a main source of criticisms against Hillary Clinton by her political rival Bernie Sanders.

Her presidential campaign used the disclosure of financial documents to rebuke the presumptive Republican nominee Donald Trump, who has not released his tax returns in recent years, something that is not required but common among American presidential candidates.

"The true test for Donald Trump is whether he will adhere to the precedent followed by every presidential candidate in the modern era and make his tax returns available, as Hillary Clinton has done," reads the campaign statement.