LIQUIDITY AND CAPITAL RESOURCES
We have historically generated substantial cash from operations, which has enabled us to fund our growth while paying cash dividends and repurchasing stock. Cash and cash equivalents totaled $494.7 million and $338.9 million as of December 31, 2008 and 2007. Available-for-sale securities, consisting primarily of highly liquid investments, totaled $2.6 million and $115.8 million as of December 31, 2008 and 2007. Working capital at December 31, 2008 and 2007 was $650.2 million and $631.5 million.
Our first priority for our cash is growing the business, as we require some working capital and a relatively small amount of capital expenditures to grow. We are continually looking for acquisitions to redeploy our cash, but those acquisitions must fit our culture and enhance our growth opportunities.
If our cash balance continues to increase and there are no significant attractive acquisition opportunities, we expect to return more of the cash to our shareholders through future dividends and share repurchases.
Cash from operating activities. We generated $447.6 million, $308.4 million, and $343.4 million of cash flow from operations in 2008, 2007, and 2006. During 2008, our cash flow from operations increased 45.1 percent compared to a 10.8 percent increase in net income. The primary factor that caused this increase in 2008 was the decrease in our accounts receivables balance of 9.1 percent to $828.9 million in 2008 from $911.8 million in 2007, as a result of declines in fuel prices and volumes at the end of 2008 compared to 2007.
Cash used for investing activities. We generated $31.5 million cash in 2008, used cash of $55.7 million in 2007, and used $81.2 million cash in 2006 for investing activities. Our investing activities consist primarily of cash paid for acquisitions and our capital expenditures. During 2008, we exited nearly all of our available-for-sale securities, and invested in cash and cash equivalents which generated $114.1 million of cash from investing activities.
We used cash of $59.7 million, $22.2 million, and $39.7 million for acquisitions in 2008, 2007, and 2006. The amount paid in 2008 included $50.2 million related to the closing of one acquisition and $9.5 million related to earn-out payments and holdbacks from prior year acquisitions. The amount paid in 2007 included $9.8 million related to the closing of one acquisition and $12.4 million related to earn-out payments and holdbacks from prior year acquisitions. The amount paid in 2006 included $29.5 million related to the closing of two acquisitions and $10.2 million related to earn-out payments and holdbacks from prior year acquisitions.
We also used $23.7 million, $43.7 million, and $43.3 million of net capital expenditures in 2008, 2007, and 2006. We spent $5.6 million, $21.1 million, and $20.4 million in 2008, 2007, and 2006 on facilities on our new corporate campus in Eden Prairie, MN. This includes the spending to date on our new data center. The remaining capital expenditures of $18.1 million, $22.6 million, and $22.9 million in 2008, 2007, and 2006 relate primarily to annual investments in information technology equipment to support our operating systems.
Cash used for financing activities. We used $326.0 million, $262.1 million, and $145.8 million of cash flow for financing activities in 2008, 2007, and 2006. This was primarily quarterly dividends and share repurchases.
We used $151.2 million, $125.2 million, and $90.8 million to pay cash dividends in 2008, 2007, and 2006, with the increase in 2008 due to a 22 percent increase in our quarterly dividend rate from $0.18 per share in 2007 to $0.22 per share in 2008.
We also used $200.8 million, $167.3 million, and $85.3 million on share repurchases in 2008, 2007, and 2006. The increase in 2008 was due to a 13 percent increase in the number of shares repurchased and an increase in the average price paid per share. We will continue to use share repurchases as a variable way to return excess capital to shareholders. Our Board of Directors has authorized a stock repurchase plan in 2007 of up to 10 million shares. We have used approximately 3.8 million shares of that authorization.
We have 3.5 million Euros available under a line of credit at an interest rate of 6.65 percent (Euribor plus 45 basis points) at December 31, 2008. This discretionary line of credit has no expiration date. Our credit agreement contains certain financial covenants, but does not restrict the payment of dividends. We were in compliance with all covenants of this agreement as of December 31, 2008.
Assuming no change in our current business plan, management believes that our available cash, together with expected future cash generated from operations and the amount available under our line of credit, will be sufficient to satisfy our anticipated needs for working capital, capital expenditures, and cash dividends in future periods. We also believe we could obtain funds under additional lines of credit on short notice, if needed.