They can attempt to put a number on it but it’s impossible to do. Billions, lots of them, is close to the mark. We have a Spotted Lanternfly infestation where I live and it’s spreading. This was the worse year by far. They were all over and destroyed a lot of grape vines across multiple counties. Don’t know if the wineries will survive. They destroyed a lot more than the grape vines. This is just one species and the spread is increasing as their numbers grow.