Germany has gone past 'Peak Telephony'

"In 2014, fixed line networks saw 154 billion outgoing minutes in Germany which is 9 billion minutes less than last year. On the mobile side they've been observing an increase of 1 billion minutes. In total that's 8 billion minutes less than the previous year, which is about -3%. The trend has been going on for quite a while now. In 2010, combined fixed and mobile outgoing voice minutes were at 295 billion compared to 265 minutes in 2014. That's 11% less over that time frame."

Source:  Mobile Society, 22nd May 2015

Note - An earlier example of other markets