Dogs really do bite mail carriers – a lot of them. According to the U.S. Postal Service, which on Wednesday released its annual report on the topic, 6,549 postal workers were attacked by dogs in 2015, an increase of 14 percent from the year before.

The letter carriers of Houston, who already must contend with humidity and a lack of sidewalks, seem to have it particularly rough. Dogs attacked 77 of them last year, making the city America’s top spot for such run-ins.

Mail carriers make up a relative drop in the bucket of the 4.5 million or so people bitten by dogs each year, according to the Centers for Disease Control and Prevention. Most are children, and most of the canine assailants are familiar to their victims. But an increase in deliveries of online purchases means more postal workers are coming face-to-face – or ankle-to-snarling mouth – with dogs.

To stem the attacks, the postal service said it’s putting in place new measures to alert mail carriers of dogs on their routes. One requires customers who schedule package pickup to indicate whether there’s a pooch at the place. The service also offered tips: Put your dog in another room when opening the door to a mail carrier, and don’t let children receive mail, because dogs can be very protective of little ones.

The service released the information ahead of an occasion known as National Dog Bite Prevention Week, which begins Sunday. State Farm, the insurance company, also released some dog bite statistics on Wednesday, saying that it paid out $118 million in dog-related injury claims in 2015.