A Fidelity Investments survey released on Thursday found that a majority of Americans do not understand how their pensions work.

While over 42 million Americans currently have pensions, 71% of the 500 surveyed by Fidelity did not have detailed knowledge of how their pension plans operate even though over half reported they are depending on those pensions to help pay for living expenses in retirement.

Fidelity, which provides service to over 4 million corporate pension plan participants, revealed that 31% of those surveyed said they don’t know their plan’s vesting schedule, 40% don’t know what their payment options will be upon retirement or when leaving their company and 27% don’t know at what age they can begin to receive payments.

“Corporate pension plans remain a critical component of retirement income for millions of Americans,” said Wendy Foster, Senior Vice President in Fidelity’s defined benefit business, in a press release. ”Our research highlights an opportunity for companies to better educate their employees about the value of employer-sponsored pension plans.

Meanwhile, 61% of those surveyed said they have never asked how much money they will receive when they retire, Fidelity reported. The reason: 43% said they rely on their employer to provide the information if needed and 29% report they aren’t knowledgeable about the plan or they do not know whom to ask for information.

With pension participants expecting their pensions to supply one quarter of their retirement income, it is worrying that so few participants understand their plans. Fifty-six percent of those surveyed said they will rely on their pension payouts to cover living expenses during their retirement years, not for travel or hobbies.

Although 56% of the pension plan participants surveyed said they expect to receive annuitized payments from their plans when they retire, 10% plan to take lump sum payments and 9% expect a combination of both, one-quarter of those surveyed said they don’t know how they will be paid.

“Understanding your pension benefits is an important part of developing an accurate income plan for retirement,” said Foster. “There are many key areas that need to be addressed and analyzed, including vesting status, preferred payment method, estate planning and the tax implications of any action.”

Fidelity services 112 employers with 674 plans. Each year, it processes more than 100,000 retirement initiations and services more than 1 million retirees.