The second calendar quarter marked the first in which BlackBerry’s debut BlackBerry 10 smartphone, the Z10, was on store shelves for the entire quarter. It was also the launch quarter of the vendor’s new BlackBerry Q10, its first next-generation handset with a full QWERTY keyboard. But during the second quarter, new data from market research firm Kantar Worldpanel suggests that BlackBerry’s U.S. market share tumbled to just 1.1% from 4% in the same quarter last year. Meanwhile, the firm says Apple’s share of U.S. smartphone sales grew to 42.5% from 39.2% in the same quarter last year despite the fact that no new iPhone has launched since last September, and Android’s share of smartphone sales fell to 51.5% from 52.6% in Q2 2012.