The average age of our tractor fleet was 2.4 years as of September 30, 2012 with all of the fleet being 2010 models and newer. The average age of our trailer fleet has improved to 3.3 years at September 30, 2012 compared to 4.2 years at September 30, 2011. We will continue to take advantage of the favorable used trailer market throughout the 4th quarter to upgrade our trailer fleet. As of September 30, 2012 we had taken delivery of 974 new Wabash trailers during 2012 including delivery of 496 during the 3rd quarter. We anticipate delivery of an additional 26 trailers in October. By the end of the year, 100% of our trailer fleet will be 2007 models or newer.
Our financial position continues to be strong. We ended the quarter with cash, cash equivalents, and long-term investments totaling $233.8 million, a $43.5 million increase from the $190.3 million reported at December 31, 2011. Long-term investments include $22.3 million of illiquid auction rate securities, at par. Since February 2008, the Company has received $176.1 million in calls, all at par. No calls were received during the third quarter of 2012. Net cash flows from operations continue to be strong at 16.5% of operating revenues. The Company's balance sheet continues to be debt-free with total assets of $546.3 million. The Company ended the past twelve month period with a return on total assets of 11.8% and a 17.9% return on equity.
Commitment to our shareholders continues through the payment of cash dividends and the purchase of our common stock. A dividend of $0.02 per share was declared during the quarter and was paid on October 2, 2012. The Company has now paid cumulative cash dividends of $349.8 million, including two special dividends, over the past thirty-seven consecutive quarters. Also, we repurchased 690,906 shares of our common stock during the quarter for approximately $9.5 million. At September 30, 2012, we had 3.9 million remaining shares under our share repurchase program.