The Internal Revenue Service said Thursday the number of tax returns electronically filed by businesses increased nearly 9 percent this year, continuing the growth in the number of corporate and partnership returns filed electronically.

This year, an additional 625,000 corporations and partnerships chose to e-file their tax returns.

As of Sept. 20, nearly 8 million corporations and partnerships e-filed their income tax returns. The IRS estimates that e-file accounts for 77 percent of all corporate and partnership returns filed during 2015. Many corporations and partnerships operating on a calendar year receive filing extensions. The due date for filing a return after filing for an extension is usually Sept. 15. Large and mid-size corporations, generally those with $10 million or more in total assets, are required to electronically file their Forms 1120 or 1120S. Partnerships with more than 100 partners (Schedules K-1) are also required to e-file their tax returns. The IRS is seeing growth in e-filing by all business segments.

This year, 100,000 large corporations e-filed their returns, a new record representing an increase of 8 percent compared to the same time last year. The largest rate of growth in e-filing among these businesses is by large partnerships. This year, 142,237 large partnerships e-filed their tax returns, up nearly 16 percent from the same time last year.

E-Filed Business Tax Returns Rose 9% This Year