WASHINGTON — The cost of mailing a first-class letter went from 50 cents to 55 cents Sunday.

It’s the largest percentage rise since 1991, when postage increased from 25 to 29 cents.

When the first Forever stamp was issued in 2007, it cost 41 cents.

A book of Forever stamps now costs $11.

Post card rates stay the same at 35 cents.

Those who buy postage online through Stamps.com will pay 50 cents for a stamp, USPS said.

Priority Mail Express rates also increased. Rates went up an average of 3.9 percent.

Rates for flat-rate envelopes for Priority Mail increase 70 cents to 72 cents.

Mailing something using a Media Mail rate will go up almost 3 percent.

The rate hike comes as the Postal Service lost $3.8 billion in 2018, its 12th year in a row of losses.

All of the new postal rates are on Stamps.com.

Here’s a look at how USPS rates changed Sunday: