I seen some technical information from G E that showed live verses output of incadesent bulbs for various percentages of voltage above and below design voltages. It is amazing how much the life changes. I attended a church where a weekly job for the pastor was replacing burned out exit light bulbs. Several a week. I replaced all the 7 watt 120 volt ones with 11 watt 130 volt bulbs and the failure rate went down to a couple a year.
