DUBLIN--(BUSINESS WIRE)--Research and Markets (http://www.researchandmarkets.com/research/973rzt/north_american) has announced the addition of the "North American Primary Line Voice Tracker: First Quarter 2015" report to their offering. In 1Q 2015, the total number of North American subscribers to both primary voice line and OTT VoIP services declined year over year (YoY), by about 2.9 million. In the US and Canada, total subscribers and revenue both declined YoY. Most of the US VoIP providers