Array
(
    [level 1: Beginner] => Array
        (
            [0] => 1
            [1] => 23
        )

    [level 2: Elementary] => Array
        (
            [0] => 24
            [1] => 39
        )

    [level 3: Lower Intermediate] => Array
        (
            [0] => 40
            [1] => 51
        )

    [level 4: Intermediate] => Array
        (
            [0] => 52
            [1] => 61
        )

    [level 5: Higher Intermediate] => Array
        (
            [0] => 62
            [1] => 69
        )

    [level 6: Advanced] => Array
        (
            [0] => 70
            [1] => 75
        )

    [level 7: Very advanced] => Array
        (
            [0] => 76
            [1] => 80
        )

)