WASHINGTON — The IRS has processed tens of millions of tax returns faster this year compared with past years while getting through to customer service on the phone is slowly improving, according to a report to Congress released Wednesday.

But there is a huge need to update the agency’s information technology services and have more workers answering calls. Still, it’s a vast improvement after years of backlogs and decades of underfunding.

The latest update on the IRS from National Taxpayer Advocate Erin Collins said the agency cut its backlog of unprocessed paper tax returns by 80%, from 13.3 million returns at the end of the 2022 filing season to 2.6 million at the end of the 2023 filing season. And now 35% of calls are answered, compared with 11% before.

“Overall, the difference between the 2022 filing season and the 2023 filing season was like night and day,” Collins said. “It marks a return to pre-pandemic levels.”

Through the climate, health care and tax legislation signed into law by President Joe Biden last year, the IRS received $80 billion for tax collection efforts.

Agency leaders started using that money immediately to add employees to the IRS workforce, which had dwindled to 1970s levels through retirements, attrition and low pay that has not caught up with inflation.

Most recently, the agency lost some of that money after the president and Congress agreed to claw back more than $20 billion in exchange for suspension of the country’s $31.4 trillion debt ceiling.

Biden administration officials have offered assurances that the spending cuts will have minimal impact on the agency’s operations over the next few years.

Earlier this year the IRS, led by new Commissioner Daniel Werfel, released details on how it planned to use its influx of money for improved operations, pledging to invest in new technology, hire more customer service representatives and expand its ability to audit high-wealth taxpayers.