Forbes have had an early look at the latest Kantar WorldPanel numbers for the 3 months ending March 2013 in the USA, and it it reads as pretty great news for Windows Phone.

Windows Phone grew 1.5% sequentially, from February 2013, more than iOS, which gained 0.2% or Android, which lost 1.9%.

Blackberry, who launched the Blackberry Z10 in March in USA, will leave terribly disappointed, having gained only 0.2% market share in March for their troubles.

Windows Phone grew from 3.7% a year ago, a more than 50% Year on Year growth.

That marks a moderately bigger increase in share than Android, whose 47.9% share of the market a year ago rose to 49.3%. Apple iOS slipped from 44.6% to 43.7% of all smartphones sold in the U.S., while BlackBerry’s share dropped form 2.6% to 0.9%.

Nokia grew its US market share to 4% on the strength of their Lumia devices, up from 1% last year.

Based on 240,000 interviews in the U.S. each year, Kantar claimed it was Windows Phone’s attraction to novice smartphone users, which is still half of the smartphone market, which was the key.

They claim that 52% of the people it surveyed who swapped to Windows from a previous OS had previously owned a feature phone vs 45% for iPhone users and 51% for new Android customers.

It’s likely that many will upgrade over the coming year, which will ultimately contribute to more growth for the Windows brand,” Kantar analyst Mary-Ann Parlato said.

Do our readers think we are heading to 10% by next year? Let us know below.