In the collectively agreed industries, e.g. IG-Metall Bayern, 35 hours are often the standard. I calculated with 222 working days at 7 hours = 1776 hours. 70,000 gross equals 43,000 net, 43,000€ / 1776h = 24.50€/h.
For 70,000€ gross, you must already be a long-serving engineer or executive within the IG-Metall tariff.
The average German earns about 40,000€ gross, 24,500€ / 222*8h = 14€/h!