Natalie DiBlasio

USA TODAY

The U.S. Postal Service delivered 28.2 million packages Monday, breaking its own record for most parcels ever delivered in a single day in its 237-year history.

The number of packages slid past the record the USPS set a week before, spokeswoman Sarah Ninivaggi said. On Dec. 15, USPS delivered 27.9 million packages, she said.

"The times are changing," Ninivaggi said. "You can see how much people are going online to buy their Christmas gifts."

Monday's deliveries marked a 10.5% increase over the same day last year and 9.5% higher than the busiest day in the 2013 holiday season.

UPS, FedEx and USPS, the nation's largest shippers, said in November that they expected more people to shop online and had prepared to handle increased demand.

"The Postal Service is doing everything we can to get the packages home for Christmas," Ninivaggi said. "This is our season. We were prepared."

Online shopping demand is higher than ever. Forrester Research, which analyzes technology companies, products and services, predicted e-commerce sales would increase 13% over 2013 to $89 billion in 2014.

UPS angered thousands of customers last year when guaranteed-delivery packages arrived days after Christmas. UPS blamed bad winter weather and a greater than expected boom in online shopping.

After last year's experience, FedEx and UPS said they made big changes to prepare for the expected surge. The U.S. Postal Service switched to seven-day package delivery after Thanksgiving, as it did last year, to accommodate the increases.

FedEx predicted its busiest day would be Dec. 15, when it expected to move 22.6 million packages.

Spokeswoman Erin Truxal said FedEx is not releasing its numbers yet.

"The investments we've made in our network, from new facilities to increased vehicles and staffing, are all paying off," Truxal said.