None of these factors, however, can sustain strong growth past 2010 without a self-sustaining cycle of private spending and income growth. Several obstacles stand in the way of that transition. Through to mid-2009 households had lost $12 trillion, or 19% of their wealth, because of the collapse in house and stock prices. That saps their purchasing power and pushes them to save more, especially those nearing retirement. Though they’ll boost their saving only gradually, that still means consumer spending (about 70% of GDP) will grow more slowly than income, after two decades in which it usually grew more quickly. High unemployment will hold back wage gains (see chart); wage cuts are already commonplace. Leaving aside swings in energy prices, inflation, now about 1.5%, will slip to zero and may turn to deflation in late 2010. Deflation drives up real debt burdens, further sapping consumer spending.