def make_year_labels(years, yearly_data, format='%d (%s)'):
    """
    Combine years with corresponding yearly data and return list of labels.

    >>> make_year_labels([2005, 2006], [18, 29])
    ['2005 (18)', '2006 (29)']
    >>> make_year_labels([2006, 2007], ['good', 'bad'], '%d was %s')
    ['2006 was good', '2007 was bad']
    """
    return [format % (y, c) for (y, c) in zip(years, yearly_data)]