Mortgage rates inched lower Friday in quiet trading. This morning, the August Producer Price Index (PPI) was unchanged from July, above the consensus forecast for a 0.2% decrease. Core PPI, which excludes volatile food and energy components, rose 0.3%, above expectations, and was 0.9% higher than one year ago. Separately, Consumer Sentiment fell sharply to 85.7. A reading of 91.0 had been expected. No other key economic data will be released today.