I believe this number is demonstrably higher. There was a recent article posted here that said that last year 850K illegal aliens graduated from our high schools. If 850K were seniors in high school, then there were even more in K5 through 11th grade (850K x 13 grades = 11,050,000). Now this figure is just the youngin's. I would wager there are 3-4 times as many that aren't in school.
You are correct. I have often told friends the number is more nearly 20 million.