$data = Array
(
    [2006] => Array
        (
            [10] => Array
                (
                    [21] => bla
                    [22] => bla
                    [23] => bla
                    [24] => bla
                    [25] => bla
                    [26] => bla
                    [27] => bla
                    [28] => bla
                    [29] => bla
                    [30] => bla
                    [31] => bla
                )

            [11] => Array
                (
                    [1] => bla
                    [2] => bla
                    [3] => bla
                    [4] => bla
                    [5] => bla
                )

        )

)