Average hourly wages were unchanged from May to June after adjusting for inflation, the latest sign of households struggling to gain purchasing power in the aftermath of the Great Recession.

The flat result stemmed from a 0.4% increase in average hourly earnings being offset by a rise in the consumer price index. Over the last 12 months, inflation-adjusted hourly wages have risen by just 0.4%.

Standard economic models hold that wages should increase during times of economic recovery and falling unemployment. But new research from economists at the Federal Reserve Bank of San Francisco finds that normal wage models don’t apply during and after recessions.