Final Fantasy XIII sold in April 91,000 units between both platfoms, that's a 93% drop 
http://www.gamesindustry.biz/articles/pressure-mounts-on-e3-to-prove-industry-can-grow-long-term
Poor April results were also due to the lack of long-tail sales for single-player games released the previous month, claims Doug Creutz of Cowan and Company, and it is online and digital strategies that can add shelf life to multiplayer titles as single-player games are traded in quickly after completion.
Sony's God of War III sold only 180,000 units last month in the US, compared to 1.10 million in March, while Square Enix's Final Fantasy XIII shifted 1.32 million in its release month, compared to only 91,000 units in April. In comparison, the multiplayer focused Battlefield: Bad Company 2 sold 1.28 million in March, and 273,000 in April.
