A reasonable question, but one that the online retailer refuses to disclose. All that Amazon reported was a 177 percent increase in holiday sales of all Kindles, which really doesn't tell us anything because the company won't provide actual numbers. Overall, Amazon reported was a 35 percent increase in revenues - short of expectations by about $1 billion. From the NYT:
Amazon, the dominant e-commerce company, is in the enviable position of growing much faster than the industry itself. But all that meteoric growth, stoked by selling goods as cheaply as possible and then shipping them either for a pittance or for free, do not leave much room for profit. Its margins have declined for four quarters before rebounding in the fourth quarter.
Even so, shares of Amazon fell sharply in after-hours trading. Question is whether the lower-than-expected revenue is a function of Amazon's particular circumstance or a reflection of a still-cautious consumer.