from typing import Dict


def get_noise_range_pcts(db_range_exps: dict, length: float) -> Dict[int, float]:
    """Calculates percentages of aggregated exposures to different noise levels of total length.

    Note:
        Noise levels exceeding 70 dB are aggregated and as well as noise levels lower than 50 dB.
    Returns:
        A dictionary containing noise level values with respective percentages.
        (e.g. { 50: 35.00, 60: 65.00 })
    """
    return {
        db_range: round(db_range_length * 100 / length, 3)
        for db_range, db_range_length
        in db_range_exps.items()
    }