What can be the maximum number of entries in boost bimap

Question

I am trying to create a boost bimap of total 177 million entries.I created a boost bimap

namespace bimaps = boost::bimaps;
typedef boost::bimap<bimaps::unordered_set_of<unsigned long long int>,
        bimaps::unordered_multiset_of<unsigned long long int> > bimap_reference;
typedef bimap_reference::value_type position;
bimap_reference reference_index_vector;

and entered the elements but it stopped entering the elements when reaching 100 million, 66 thousand entries. I would like to know if there is any maximum limit of boost bimap, or there can be some other problem.