Users of Apple’s iPhone smartphones and its iPad line of tablets accounted for 92% of all mobile purchases made thus far in December, a recent study by eCommerce company RichRelevance found. That figure is up from April 2011 when a similar study conducted by the firm found that Apple’s iOS devices accounted for 88% of non-desktop online shopping. Beyond being more frequent shoppers, RichRelevance also found that iOS users are bigger spenders than their Android counterparts — the average purchase made from an iOS device was $123 in December while the average Android-originated mobile purchase amounted to $101. Both iOS users and Android users top those who shop from desktop PCs, as they spent an average of just $87 per order in December according to the company. Overall, RichRelevance found that shopping from mobile devices has doubled from 1.87% of all online shopping to 3.74% over the past nine months.