The deaths of twin girls last week brought this year’s total to 26, two higher than in all of 2015.

Twin 15-month-old girls in Carrollton, Ga., Thursday became the 25th and 26th children nationwide to die this year after being trapped in a hot car.

That’s two more than all the hot-car deaths last year, according to organizations that track such cases.

The previous hot-car deaths have been just as heart-wrenching as what happened to Ariel Roxanne North and Alaynah Maryanne North. Just last month, for example, 2-year-old Boi Lei Sang died in a church parking lot in Dallas while his parents attended worship services. When he couldn’t find his son in Bible class, the child’s father bolted out of the church and found the toddler unresponsive and overheated in the family SUV.

Boi Lei was one of four children to die in a four-day span last month, with the other deaths occurring in Florida, Missouri and Pennsylvania.

On average, 37 children a year die from heat-related deaths inside cars. And last year’s total of 24 was the lowest in any single year since 1997.

Jan Null of the meteorology and climate science department at San Jose State University in California, attributes last year’s decline to the nationwide publicity about the 2014 Ross Harris hot-car murder case in Cobb County, Ga. Harris is accused of deliberately leaving his 22-month-old son, Cooper, to die in his family’s sweltering SUV in 2014. Harris’ trial begins Sept. 12.

“There was so much attention across the nation on the Harris case I believe it raised public awareness,” said Null, who closely tracks hot-car deaths.

He said, however, that the trend of three dozen deaths annually has returned this year.

“For the first week of August, with 26 so far, we’re right at about average,” Null said. “Sadly, we’ll probably see another half-dozen deaths this year, if not more.”

The Carrollton twins’ father, Asa North, is charged with two counts of involuntary manslaughter and reckless conduct, and police say alcohol played a role in the tragedy.