Research firm Gartner said worldwide smartphone sales to end users represented 13.5 percent of all mobile device sales in the first quarter of this year, up from 11 percent in the first quarter of last year. In the above chart, all figures are in thousands, and Gartner said it is only counting HTC's self-branded devices, including the G1.
Source: Gartner [1]
Links:
[1] http://www.gartner.com/it/page.jsp?id=985912
[2] http://www.fiercewireless.com/story/gartner-handset-sales-down-smartphone-surge/2009-05-20