Bajaj Auto on Monday reported a marginal decline in total sales in December at 2,89,003 units as against 2,89,244 units during the same month last year. However, motorcycle sales during the month increased by 1 per cent to 2,47,782 units as against 2,46,233 units in the same month in 2014, company said. Bajaj Auto’s commercial vehicles sales stood at 41,221 units compared with 43,011 units in the year-ago period.