Hillary and Bill Clinton have earned at least $30 million since January 2014, including more than $25 million for delivering about 100 speeches, according to a government filing.

Hillary Clinton, the front-runner for the Democratic presidential nomination in 2016, has earned more than $5 million in royalties for her book, "Hard Choices," which was published in June, according to the form.

The Clintons' income puts them at the upper end of the top 0.1 percent of earners in the US population, according to government data.

Economic inequality has emerged as an early theme with candidates of both parties vying for the White House in November 2016.

The "one percent" has become a talking point in policy discussions about the divide between rich and poor, cited by politicians to support everything from increased Wall Street oversight to raising wages to overhauling the tax code.

Clinton announced her candidacy last month by saying "everyday Americans need a champion and I want to be that champion."

In early campaign stops, Clinton has said how she believes the "deck is stacked" against middle class Americans and that it is time to "reshuffle the cards."

The Clintons themselves have faced criticism for their privileged status. Last year, Hillary Clinton said they were "dead broke" when they left the White House in 2001, even though Bill Clinton made millions of dollars giving speeches after his presidency.

Clinton, a former top diplomat, US senator and first lady, has earned as much as $250,000 per speech since leaving the State Department in 2013.

Paid appearances at financial institutions such as Goldman Sachs and Bank of America in particular have drawn fire from the liberal wing of the Democratic party, which fears her campaign will be beholden to moneyed interests.

Clinton, like all presidential candidates who entered the race before April 15, was required to file an account of her personal finances by May 15.

The Clinton campaign made the filing available to media outlets for review.

The Federal Election Commission forms ask candidates to report the values of assets and liabilities in broad ranges, making it impossible to arrive at a candidate's exact net worth.

The minimum value of the Clinton's financial assets is $11.3 million, but their net wealth is likely far more, since the value of some assets, including personal residences, are not required to be reported and anything above $5 million is reported in a single category.