Not sure what you mean by the % now? Wales is going to lose 28% of its MP's in the UK parliament.
Putting it in numbers, Wales has 40 MP's in the UK parliament out of 650 MP's. We will lose 11 MP's giving us 29 out of the 600 that will be sitting in the UK Parliament.
Welsh Government only deals with devolved issues - many of which have just been clawed back by the UK Government in readiness for Brexit, and of course there will be no MEP's after March.