Two years ago, when Mara DeMers of Elk River scored a perfect 36 on her ACT college entrance exam, her kid sister Anessa was taking note.

This year, Anessa matched the feat.

ACT administrators say perfect scores were achieved about 700 times last year by the 1.6 million people who took the exam.

"When you consider the infinitely small percentage of students who earn a perfect score, that is very rare," ACT spokesman Ed Colby said. "For two sisters to have earned perfect scores, that is beyond extremely rare."

The exam consists of tests in English, math, reading and science. Each is scored on a scale of 1 to 36, and a student's overall result is the average of the four scores. Students can retake the test to try to get a better score. That's what Mara did, reaching perfection on her second try.

The sisters say they're not competitive. Actually, Anessa said they're not. Mara said, "She is. I'm not."

That could be. Their mom, Sue Lavenz, noted that on the day the scores came out, Anessa wrote on her Facebook wall, "OK, officially I'm the smarter sister. I got the 36 on the first try."

"When she's living in her sister's shadow all these years, she was so stressed out that she wouldn't do as well," Lavenz said.

At the same time, Lavenz said, the sisters, separated by three years, are "best friends."

Anessa did say she was inspired by her sister's accomplishment.

"We support each other a lot," she said. "We know we're both smart, so if she could do it, I thought I could do it, too."

Mara, a third-year plant biology student at the University of Minnesota, said she didn't coach her sister.

"I didn't really advise her. She learns pretty well on her own."

Lavenz said that for both her daughters, the scores were a nice affirmation.

Their dad, Robert DeMers, works in avionics at Honeywell. Yes, an actual rocket scientist.

Lavenz runs Stable Living, a stable and riding school in Nowthen.

It was important to mom and dad, when the girls were younger, to read to them and do their best to answer questions or look up the answers together.

"Just what a lot of parents do," Lavenz said. "They do very well at what they do, and we're very proud."

Anessa has one more year left at Elk River High School. After that, she said, she's hoping to study creative writing at Johns Hopkins University in Baltimore.

Staff writer Paul Walsh contributed to this report. Maria Elena Baca • 612-673-4409