For charitable work:

2018: remains at 14 cents per mile as fixed by law [Code Section 170(i)]

Hurricane Katrina related:
For deduction purposes            For reimbursement purposes
2006                          32 cents                                              44.5 cents
9/1 to 12/31/05 34 cents                                              48.5 cents
8/25 to 8/31/05 29 cents                                              40.5 cents

12 cents per mile for years before 1999