Congress paid out $15 million in settlements. Here’s why we know so little about that money.

(CNN) — Two things have become painfully clear on Capitol Hill this week: Lawmakers and staffers say sexual harassment is “rampant” — but even members of Congress have no idea just how widespread the problem is.

The controversial and sensitive issue has taken center stage in Congress this week, with female lawmakers making fresh allegations of sexual harassment against unnamed members who are currently in office, and the unveiling of a new bill on Wednesday to change how sexual harassment complaints are reported and resolved.

So far, there’s been little specific data to help illuminate just how pervasive sexual harassment is on Capitol Hill, but one figure has emerged: More than $15 million has been paid out to victims through the Office of Compliance, the office that handles harassment complaints. That $15 million figure includes all settlements, not just related to sexual harassment, but also discrimination and other cases.

CNN has also learned that during the current Congress, no settlement payment approval requests have been made to the congressional committee charged with approving them.

Here’s what we know — and what we don’t know — about that money:

When was this money paid out?

According to a report from the Office of Compliance, more than $15 million has been paid out in settlements over a period of 20 years — 1997 to 2016.

How many settlements have there been?

Rep. Jackie Speier, the California Democrat who on Wednesday unveiled a bill to reform the OOC, announced at a news conference Wednesday that there have been 260 settlements, and an aide to the congresswoman confirmed that those settlements represent the number reached over a period of 20 years.

Where did the $15 million come from?

Taxpayers. Once a settlement is reached, the money is not paid out of an individual lawmaker’s office but rather comes out of a special fund set up to handle this within the US Treasury — meaning taxpayers are footing the bill. The fund was set up by the Congressional Accountability Act, the 1995 law that created the Office of Compliance.

How many of the settlements were sexual harassment-related?

It’s not clear. Speier told CNN’s Wolf Blitzer on Wednesday that the 260 settlements represent those related to all kinds of complaints, including sexual harassment as well as racial, religious or disability-related discrimination complaints. The OOC has not made public the breakdown of the settlements, and Speier says she’s pursuing other avenues to find out the total.

Who knows about the settlements and payments?

After a settlement is reached, a payment must be approved by the chairman and ranking member of the House administration committee, an aide to Chairman Gregg Harper, a Mississippi Republican, told CNN.

The aide also said that “since becoming chair of the committee, Chairman Harper has not received any settlement requests.” Harper became chairman of the panel at the beginning of this year.

It’s not clear how many other lawmakers — if any — in addition to the House administration committee’s top two members are privy to details about the settlements and payments.

A source in House Speaker Paul Ryan’s office told CNN that Ryan is not made aware of the details of harassment settlements. That source also said that the top Democrat and Republican on the House administration committee review proposed settlements and both must approve the payments.

Similarly, a source in Minority Leader Nancy Pelosi’s office told CNN that Pelosi also is not made aware of those details, and that they are confined to the parties of the settlement and the leaders of the administration committee.

“Leader Pelosi has expressed support for the efforts of Rep. Speier who is working on multiple bills to reform the secretive and woefully inadequate process,” the source added.

When asked about Ryan’s knowledge of any sexual harassment settlements, a spokesperson for Ryan’s office noted that the committee is conducting a full review of workplace harassment and discrimination.

What do these settlements tell us about the scope of the sexual harassment problem on Capitol Hill?

It is unclear how much of the $15 million is money paid to sexual harassment cases because of the Office of Compliance’s complex reporting process. However, even knowing that dollar figure doesn’t quantify the problem: a source within the Office of Compliance tells CNN that between 40 and 50% of harassment claims settle after mediation — an early stage in the multi-tiered reporting process.

And the number of settlements reached may not be indicative of how widespread sexual harassment is, as many victims chose not to proceed with OOC’s process for handling complaints. Tracy Manzer, a spokeswoman for Speier, told CNN last week 80% of people who have come to their office with stories of sexual misconduct in the last few weeks have chosen not to report the incidents to the OOC.