With that, I'll turn the call over to Mike Dubyak.
Good morning, everyone, and thanks for joining us. By all accounts, 2011 was a strong year Wright Express. For the full year, revenue grew 42% and adjusted net income grew 32%. This compares to our initial guidance for 2011 of revenue growth of 30% and adjusted net income growth of 19% at the midpoint of the ranges.
This performance was driven by continued execution against our multi-pronged growth strategy to expand our North American fleet business, diversify our revenue streams and build out our international presence. We experienced transaction growth of 8%, added another large travel client in our Other Payment Solutions segment and had the impact of the acquisitions of Wright Express Australia in 2010 and rapid! PayCard last year.
For the fourth quarter, revenue came in at the top end of our guidance range and earnings exceeded our expectations. Revenue grew 22% to $140 million and adjusted net income increased 33% to $38 million or $0.98 per share.
During the quarter, we once again saw strong growth from our corporate charge card product in our Other Payment Solutions segment and steady growth in our Fleet segment. In addition, we saw improved performance in our credit trends.
We're viewing some key metrics. Consolidated payment processing transactions increased 3% over the prior year. Existing customer gallons domestically or same-store sales was down approximately 0.4%, an improvement from the third quarter. We believe this continues to be reflective of the overall economic picture.
Taking a look at our same-store sales by SIC code, we had mixed results in our two largest concentrations. Business services was slightly negative for the quarter, and construction was slightly positive for the quarter. Also positive, transportation was up 3%, which is generally considered a good indicator for the economy.