def find_endurance_tier_iops_per_gb(volume):
    """Find the tier for the given endurance volume (IOPS per GB)

    :param volume: The volume for which the tier level is desired
    :return: Returns a float value indicating the IOPS per GB for the volume
    """
    tier_description_split = volume['storageTierLevel']['description'].split()

    if tier_description_split != []:
        iops_per_gb = tier_description_split[0]

        if iops_per_gb == '0.25':
            return 0.25

        if iops_per_gb == '2':
            return 2.0

        if iops_per_gb == '4':
            return 4.0

        if iops_per_gb == '10':
            return 10.0

    raise ValueError("Could not find tier IOPS per GB for this volume")