* Annual retail turnover still up 9.4% * Australian banks card spending data point to pick up in January * Retail sales seen contributing to Dec qtr GDP growth- economists (Adds economist comment, A$ reax) SYDNEY, Jan 22 (Reuters) - Australian retailers suffered their biggest sales drop in eight months in December, recoiling after consumers brought forward their Christmas shopping although timely card spending data by banks point to a rebound in the New Year. The 4.2% month-on-month drop in sales was spread across five of the six retail categories, led by household goods, department stores and clothing, the Australian Bureau of Statistics (ABS) reported on Friday.