What is the mintage (bu) with the artist Royal Canadian Mint Staff and has an issue price (proof) of $54.95?
create table table_11916083_1 (mintage__bu_ varchar, _clarification_needed_ varchar, artist varchar, issue_price__proof_ varchar, PRIMARY KEY (mintage__bu_))
select mintage__bu_[_clarification_needed_] from table_11916083_1 where artist = "royal canadian mint staff" and issue_price__proof_ = "$54.95"