@staticmethod
def make_label(years_ago):
    """
        Convert a number of years ago into a label.

        E.g: -1000000 -> 1 Mya
        """
    import locale
    locale.setlocale(locale.LC_ALL, '')
    if years_ago <= -1000000:
        value = round(years_ago / -1000000.0, 2)
        output = locale.format_string('%0.4g mya', value, grouping=True)
    elif years_ago == 0:
        output = 'present'
    else:
        output = locale.format('%d', years_ago * -1, grouping=True) + ' ya'
    return output
