The Australian dollar flirted with six-year lows on Friday as booming car sales and worse-than-expected retail figures offered a mixed message for the strength of the Australian economy. The dollar was trading at US75.88 on Friday afternoon after bottoming out at US75.67 around midday - just above the six-year low of US75.32 on April 2. Vehicle sales in June were up 6.4 per cent up on May and up 3.3 per cent year-on-year, with 125,850 vehicles sold, according to new figures from the Federal Chamber of Automotive Industries.