costs, offset by investments we make in longer-term strategic initiatives, which generally requires us to hire additional software engineers, computer scientists and merchandisers. To increase product sales, we focus on improving all aspects of the customer experience, including lowering prices, improving availability, offering faster delivery times, increasing selection, increasing product categories, expanding product information, improving ease of use, and earning customer trust. We generally focus on growing gross profit and operating profit dollars rather than maximizing margin percentages. Because we have deferred tax assets from net operating loss carryforwards, the free cash flow impact from income taxes paid is currently less than our income tax provision. 

We also seek to efficiently manage shareholder dilution while maintaining the flexibility to issue shares for strategic purposes, such as financings and aligning employee compensation with shareholders’ interests. We utilize restricted stock units as our primary vehicle for equity compensation because we believe they better align the interests of our shareholders and employees. Restricted stock units result in charges to our consolidated statements of operations based on the fair value of the awards at the grant date recorded on an accelerated basis over the underlying service periods, net of estimated cancellations. Total shares outstanding plus outstanding stock awards were 436 million and 438 million at December 31, 2006 and December 31, 2005. These totals include all stock awards outstanding, without regard for estimated forfeitures, consisting of vested and unvested awards and in-the-money and out-of-the-money stock options. In 2006, we repurchased 8 million shares of our common stock under a repurchase program authorized by our Board of Directors. 

We seek to reduce our customer experience variable costs per unit and work to leverage our customer experience fixed costs. Our customer experience variable costs include product costs, payment processing and related transaction costs, picking, packaging, and preparing orders for shipment, transportation, customer service support, and most aspects of our marketing costs. Our customer experience fixed costs include the costs necessary to build, enhance, and add features to our websites and build and optimize our fulfillment centers. Variable costs generally change directly with sales volume, while fixed costs generally increase depending on the timing of capacity needs, geographic expansion, category expansion, and other factors. To decrease our variable costs on a per unit basis and enable us to lower prices for customers, we seek to increase our direct to publisher and manufacturer sourcing, maximize discounts available to us from suppliers and reduce defects in our processes. To minimize growth in fixed costs, we seek to improve process efficiencies and maintain a lean culture. 

Because of our model we are able to turn our inventory quickly and have a cash-generating operating cycle. On average, our high inventory velocity means we generally collect from our customers before our payments to suppliers come due. Inventory