Mortgage rates inched higher Thursday in volatile trading. This morning, payroll firm ADP estimated private sector job growth of 325,000 in December, doubling forecast. However, ADP has had a mixed record of accuracy with past predictions for the Employment Report, which is due out Friday. Weekly Jobless Claims fell to 372,000, close to expectations. The Institute for Supply Management services index rose to 52.6, slightly below forecast. Readings above 50.0 indicate expansion in the services sector of the economy. No other key data will be released today.