Over the last 200 - 300 years the main driver behind changing this number was technological progress - we learned to produce things better with fewer people involved, less materials used, etc.. (politics.stackexchange.com)
That's because social support and love are probably the key drivers behind many of the positive findings in comparison studies of singles, married, living together and divorced women. (lovein90days.com)
One of the primary drivers behind mortgage refinancing is to lower your monthly mortgage payment. (thecollegeinvestor.com)