Laravel 5.1 - Need help to convert Raw Query to Eloquent

Can someone help me to convert this Raw Query to Eloquent? Thanks!

Raw Query:

$data = DB::select('
    select prefix, mobile, doubles, count(*) as numbers
    from contacts
    join (
        select count(*) as doubles
        from (
            select count(*)
            from contacts
            group by prefix, mobile
        ) as t1
    ) as t2 on contacts.id
    where group_id = 1
    group by prefix, mobile
    limit 5
');

via Chebli Mohamed