Poverty, "relative poverty", and opportunity. Clearly as long as you define poverty as the lowest 10% of income, you will always have darn close to 10% poverty, right?
Stumbling and Mumbling points out that the above logic is in error. Providing benefits to bring everyone up to 61% of the median income would solve that statistical issue by eliminating the bottom. Of course, the disincentives to work provided by those benefits, and the disincentives to work which would be required via taxes, would make everyone far poorer in the end.
Take a look at his piece, and read the comments. The problem, of course, lies in not defining poverty by standard of living.