Nearly 100 days into his term, President Donald Trump hasn't nominated anyone for 85% of key executive branch positions that require Senate confirmation.

Of the 554 positions requiring confirmation, as of Saturday, 473 have no nominee, 35 have been announced but not formally nominated, 24 have been nominated, and just 22 have been confirmed thus far, according to a database put together by the Washington Post and the nonpartisan Partnership for Public Service.

By this point in his first term, former president Barack Obama had 120 people nominated and just 54 confirmed, according to data provided to Business Insider by the Partnership for Public Service.

Having a high number of unfilled positions across federal agencies is not a catastrophic risk in the short term, experts say, because while political appointees await Senate confirmation, the administration has the power to appoint acting individuals to executive agency roles.

In other words, while the positions are unfilled, they are not vacant and are almost always occupied by career people who are chosen by the president from a narrowly-defined pool of individuals, while the president's nominee is vetted by the Senate.

But experts warn the greatest risk in unfilled roles lies in handling crisis situations or enacting long-term policies.

And the delay could be creating the No. 1 thing Trump hates about government — inefficiency.

What are the risks?

View photos Trump Cabinet Positions Filled More

Some key departments have almost no Trump-appointed staffers. The Department of State, for example, has 119 positions that require Senate confirmation. So far, three have been confirmed, including Secretary of State Rex Tillerson and UN Ambassador Nikki Haley.

The Department of Defense, which consists of 53 key positions, has had just one nominee — the Secretary of Defense, James Mattis — confirmed, while two others have been nominated but not confirmed, and one has failed. No one has yet been nominated for the other 49 positions in the agency.

"In virtually all unfilled positions, there will be an acting individual who is performing the functions of the job, but it's like having a substitute teacher," Max Stier, CEO of the Partnership for Public Service and the Center for Presidential Transition, told Business Insider. "They're not perceived as having long-term authority and they don't view their jobs as lasting, so they're not going to be making judgments based on a long term vision, or making hard choices."

It's like having a substitute teacher.

The importance of having political appointees across executive agencies applies not just to the top-most cabinet positions, but also to these sub-cabinet positions, especially when it comes to enacting new policy changes — like those outlined in Trump's 24 executive orders.