Verizon reported iPhone activations of 6.2m, 9.8m total smartphones and ~11.4m retail postpaid phones sold in the December quarter. That means that iPhones were 63% of smartphone activations and 55% of all postpaid phone volume. This is obviously much higher than the iPhone's global share, due to the unique pricing environment in the USA.
Interestingly, this is the highest share that the iPhone has ever had at Verizon. Share did spike last year with the iPhone 4S launch, but not by as much.
Verizon also said that half of the iPhone sales were of old models, a surprisingly high figure. It may be that both this and the dramatically higher sales are a little exceptional: December was the first quarter in which Verizon was selling an older iPhone model discounted to zero (after subsidy), since this was the first quarter that the last-but-one model (the iPhone 4) was available in a CDMA version (the 3GS was GSM-only)*.
In other words, a surge in pent-up demand for a 'free' iPhone at Verizon (and, by extension, Sprint) would result in a surge in demand focused on the older model, that would not be replicated globally. This means there's little likelihood that the sales of the lower (absolute) margin iPhone 4 are increasing more generally. On the other hand, we cannot yet tell how much of the higher share is a one-off and how much the continuing availability of the 'free' iPhone on Verizon will mean ongoing higher share. Probably a bit of both.
Overall, smartphones carried on growing as a percentage of sales, though at over 85% of total phone sales there's only so much more room for growth.