Home values are falling for more than half of America — the biggest share since the country was still clawing its way out of the Great Recession.New data from Zillow shows that 53 percent of US homes have lost value over the past year, the highest level since 2012, when the housing crash finally hit bottom.The national market looks flat on paper, but that average masks huge differences between regions, cities and even neighborhoods. Prices have been slipping in much of the South and West as more homes hit the market and buyers stay on the sidelines. Many would-be buyers...