Our personnel expense decrease was driven by declines in various incentive plans that are designed to keep expenses variable based on growth in earnings, offset partially by an increase in our average headcount of approximately nine percent. Other operating expense growth was driven primarily by an increase in travel expenses and claims, partially offset by a decrease in the provision for doubtful accounts.
From July 1 through July 23, 2012, our North American truckload volume growth per business day was approximately 11 percent. Through the same period, our total net revenue per business day declined approximately 1.5 percent.
Founded in 1905, C.H. Robinson Worldwide, Inc., is one of the largest non-asset based third party logistics companies in the world. C.H. Robinson is a global provider of multimodal transportation services and logistics solutions, currently serving over 37,000 active customers through a network of 234 offices in North America, South America, Europe, Asia, and Australia. C.H. Robinson maintains one of the largest networks of motor carrier capacity in North America and works with approximately 53,000 transportation providers worldwide.
Except for the historical information contained herein, the matters set forth in this release are forward-looking statements that represent our expectations, beliefs, intentions or strategies concerning future events. These forward-looking statements are subject to certain risks and uncertainties that could cause actual results to differ materially from our historical experience or our present expectations, including, but not limited to such factors as changes in economic conditions, including uncertain consumer demand; changes in market demand and pressures on the pricing for our services; competition and growth rates within the third party logistics industry; freight levels and increasing costs and availability of truck capacity or alternative means of transporting freight, and changes in relationships with existing truck, rail, ocean and air carriers; changes in our customer base due to possible consolidation among our customers; our ability to integrate the operations of acquired companies with our historic operations successfully; risks associated with litigation and insurance coverage; risks associated with operations outside of the U.S.; risks associated with the potential impacts of changes in government regulations; risks associated with the produce industry, including food safety and contamination issues; fuel prices and availability; the impact of war on the economy; and other risks and uncertainties detailed in our Annual and Quarterly Reports.