Consumer Intelligence Research Partners released a report on Monday revealing new details about iPhone users. Among those surveyed as part of the firm’s study, 21% of iPhone 4S buyers bought the 64GB model and 36% of new iPhone buyers came from another platform such as Android, BlackBerry or Windows Phone. The research firm previously found that 18% of buyers who bought the iPhone 4S at launch came from another platform. Online purchases of the device represented 43% of Apple’s total handset sales during the iPhone 4S launch, dropping to 33% by the of 2011. The survey also found that AT&T, Verizon and Sprint have all maintained steady market shares regarding iPhone ownership, however, and the device has apparently helped each carrier take customers from other carriers that do not carry the iPhone, such as T-Mobile. CIRP surveyed over 6,000 customers who bought an iPhone between October and December last year.