In following the NPD data it is interesting to see the spoikes in retail share percentages at the major SDARS holiday periods. Sirius has traditionally spiked in retail share during these periods.
It seems that when the holidays happen that Sirius gains a distinct advantage over XM, and this has been happening for quite some time.
This June Sirius spiked up to a 61% share...up from 55% in May.
Look at the share data at - http://siriusbuzz.com/june-npd-released.php