How many seven year old triplets are in the US?

As of the most recent estimates, there are approximately 4 million births per year in the U.S., with triplet births being relatively rare, accounting for about 1 in every 8,000 births. This suggests that there are roughly 500 to 600 sets of triplets born each year. Given this, it can be estimated that there are around 3,500 to 4,200 seven-year-old triplets currently in the U.S. However, precise numbers can vary based on specific birth statistics and trends.