Click here to write a Letter to the Editor. The producer price index fell 0.6% in January, but the “core” rate rose, the Labor Department reported Friday.The core PPI, which excludes food and energy, rose 0.2% for the second straight month, Labor said.The overall PPI decline followed a 0.9% increase in December.The figures matched economists’ forecasts, Bloomberg reported.An increase in the PPI could indicate strong demand for goods, which would mean more shipments for trucking companies. However, if inflation begins to accelerate too quickly, it could also hurt the economy.