FYI, for the States at least, $2000/mo is too high. It always strikes me... I don't think people who make good money often understand just how poor most people really are. The lower 50% of U.S. tax payers only average around $15,000/yr. If I were to guess, approx. 50% of the poverty level would make a good peg. I also think parent should get additional allowances for no more than two children.
That said, the system has a tendency to balance itself (the marvels of free-market capitalism when allowed to work properly) so no mater how much was granted per month, the system could self-adjust. Unfortunately there are so many entrenched interest gumming up the works these days, I'm not sure anything about the markets are really working "freely" as they should.