Football is the most popular high school sport in the country. However, there are reasons to believe that it’s just not quite as popular as it once was.

According to a survey released by the National Federation of State High School Associations (h/t Football Scoop), the number of high school students participating in football is the lowest it’s been since 1999. There were 1,006,013 students on the rosters of the 14,247 high schools that had 11-man football in 2018.

That seems like a large number, but it’s actually been steadily declining since 2008, when there were 1,112,303 high school football players in the country. And in 1999, there were 1,002,734, which was the last time there was a number as low as 2018.

However, as Football Scoop points out, the population of the United States was 279.3 million in 1999 and an estimated 327.2 million today.

If this trend continues, then the number of high school football players in the country could soon dip below 1 million for the first time since 1998.

It’s possible that this decline in participation could be due to health-related concerns, as parents don’t want their children to potentially sustain serious injuries while playing football.