sub _select_fields
    {
        my $self = shift;
        my %rev_types = (
            both    => [ qw/rev  theater_avg  num_theaters/ ],
            total   => [ qw/rev               num_theaters/ ],
            loc_avg => [ qw/     theater_avg  num_theaters/ ],
            all     => [ qw/rev  theater_avg  num_theaters  day_multiple/ ],
        );

        my $rev_type = $self->request->param('rev_type');
        $rev_type    = 'both' unless exists $rev_types{$rev_type};
        return @{$rev_types{$rev_type}};
    }