Nokia does not give any hard numbers for Lumia Windows Phone sales this time, but it says very clearly that the reason for the decline in Lumia sales lies in the “strong momentum of competing smartphone platforms” (Android and iOS, obviously). Put simply, Nokia admits that it is the Windows Phone platform’s lack of momentum that slows down sales.
Nokia’s handset unit, now part of Nokia's discontinued operations, registered a 30% sales decline to $2.66 billion (€1.92 billion) in the first quarter. It contributed for a widening operating loss of €326 million, compared to a €73 million loss in the same period last year.
Of feature phones and smartphones, Nokia says the loss was mostly due to a stark decline in feature phone sales, and to a lesser extent - due to declining smartphone sales.
Interestingly, Nokia smartphone sales have increased from the 5.6 million units it sold in Q1 2014, but average selling price has gone down. We’d guess that this has a lot to do with affordable smartphones like the Nokia Lumia 520 making a large chunk of Lumia overall sales. Feature phones declined in both volume and average selling price.
source: Nokia (PDF)