Yes! I was lucky enough to get a tour of the NIF, and I asked the guide what the conversion efficiency was of the UV conversion (as those can be pretty inefficient), and he said 50%. Think about that - you go through the whole multi-building-sized process of building hundreds of terawatts of laser beams, and the last step - like 25 feet from the target it looked like - you lose HALF of the energy to UV-upconversion. Then 90% of the X-ray energy is lost. So you've got to start with a LOT of laser power. See https://lasers.llnl.gov/about/how-nif-works/final-optics.