I do not have the numbers on the top of my head, but I think the amount of time allocated to the Russian Space Agency itself would be 0. There may be Russian participation in some proposals for observation - you should check the stsci.edu site since the Space Telescope Science Institute is responsible for executing the time allocation process.
Hubble time is allocated via a peer reviewed process.
Check the stsci site above for more information. Basically, proposals are submitted, then a panel of astronomy experts review the proposals, and the ones with the most merit get the time. The proposals are judged on scientific merit and not the affiliation of the proposers, so in principle, members of the general public can participate. In practice, one needs to know a lot of detail about the telescope and the scientific topic you want to study before a proposal can compete successfully.