I don’t have much experience with poker rooms, but with casinos I think most of the time you can have ratios like 1 RMP for 5 downloads or even better.
There is a thread on the general discussion in which webber286 said:
our download issue could be a couple of things. First, when you click on the download link, the software automatically starts downloading, which might not be what the user intended by going there. Second, the file that downloads is a pre-downloader that requires the user to run it to download the actual software. Given this extra step, you might be experiencing some less adept users not sure what to do.
If you promote poker rooms where the download starts without the user noticing it, your ratio may be much worse since the download count is not real.