My gf works for a recruitment company in the Netherlands, and my general feeling looking at these results is that they're on the low side. Senior developers here charge in the region of 50-70 euros/hour, or about 450 euros/day. I'm fairly sure a senior with plenty of experience in an in-demand technology can push the 70 up into the 80-90 rate, and niche areas like SAP can be even higher.