Some argue that the washing machine was the greatest invention of the industrial revolution[1], because it freed up the time traditionally spent by half the worlds population to do more productive tasks, such as learn to read.

Female literacy levels is a good leading indicator of social and economic development[2].

[1] http://www.businessinsider.com.au/hans-rosling-washing-machi...

[2]] http://en.wikipedia.org/wiki/Socioeconomic_impact_of_female_...