Over the past several years, we’ve watched the rate at which autism is diagnosed raise exponentially from 1 in 150 children in 2000 to 1 in 68 as of 2014. However, a new number being batted around that was calculated by the government paints an even direr picture: according to the report, 1 in 45 children in the U.S. have autism.

This figure, which was released on Friday November, 13 comes from the Centers for Disease Control and Prevention, which also provides two other estimates with the most rigorous number being the 1 in 68 figure (a third figure puts the rate at 1 in 50). This latest number comes from a survey of parents of 13,000 children, who were asked last year if their child was ever diagnosed with autism or a related disorder. The lower 1-in-68 estimate was the result of CDC researchers reviewing the health and school records for over 47,000 children.

While the 1 in 68 number will still be treated as the best estimate, some experts, including Michael Rosanoff, who is the director of public health research at Autism Speaks, believes that the new figure supports the growing belief that 1 in 68 is actually an underestimate.

In an interview, CBS medical contributor Dr. David Agus states that some of the discrepancy is likely due to changes in the way parents were surveyed. “The questionnaire changed from 2013 to 2014,” said Agus. “They changed the order of the questions, and some of the questions. So parents who had said they had a child with an ‘other developmental delay’ were now switching them into the autism box. So it went from 1 in 68 to 1 in 45. The disease incidence isn’t changing, but certainly our awareness [is].”

For decades, autism meant children with severe language, intellectual, and social impairments and unusual, repetitious behaviors. But the definition has gradually expanded and now includes milder, related conditions. The cause or causes of autism are still not known.

According to experts, it is becoming far more common for teachers and parents to view a child’s behavior and classify it as possibly autistic, which is emblematic of a change in parental labeling that was far less prevalent a decade ago. In addition, the CDC report notes that children are included in the most recent estimate if they ever at any time received a diagnosis of autism. This means the figure includes those that may not be considered to have autism any more.

“There are many reasons children who received a diagnosis in the past may no longer meet the criteria for a diagnosis, including, but not limited to, maturation, misdiagnosis, and effective treatment,” the authors say.

Nonetheless, increased awareness and diagnoses are ultimately beneficial for children with autism and their families; by identifying autism earlier, the chances for intervention improve and so do the possibilities of a better result.