MEXICO CITY, Jan 11 (Reuters) - AeroMexico, Mexico's top airline, transported 14.8 million passengers in 2012 - missing an already reduced goal of 15.5 million - its parent Grupo AeroMexico said in a release on Friday. The carrier, which in March of last year had projected annual passenger traffic of 16 million, did not detail why results came in weaker than expected. In December, one of the busiest travelling periods in Mexico as families take Christmas holidays, domestic traffic fell nearly 2 percent from a year earlier, while international flights inched up 0.5 percent. AeroMexico has aggressively expanded in the market since the 2010 demise of its rival Mexicana, which stopped flying buried under a pile of debt. Grupo AeroMexico, which listed 17 percent of its capital in the Mexican stock exchange in 2011, placed last year an order valued at around $11 billion for up to 100 new Boeing planes -- 90 737 MAX 8 planes and 10 787-9 Dreamliners. In November, it finalised an order for 60 737's, with an option for the remaining 30 pending. Last month, it closed an order for six 787-9 Boeing Dreamliners, with the first delivery expected in the summer. the purchase of four additional Dreamliners has yet to be confirmed. AeroMexico shares slipped 0.16 percent to 19.25 pesos in the Mexican stock exchange Friday afternoon.