Furthermore, although the total number of illiterate adults is decreasing worldwide, the proportion of women remains constant at around 64%.

UNESCO: Michelle Bachelet and Princess Laurentien of the Netherlands to attend anniversary of UNESCO��s Global Partnership for Girls�� and Women��s education | United Nations Educational, Scientific and Cultural Organization

Because handedness has a genetic component the researchers wondered why the proportion of left-handers should have remained so constant over 30, 000 years - the age of the oldest cave studied.

BBC: Cave handprint, Montpellier University

If AR had been growing only in proportion with revenue, days to pay should have remained roughly constant.

FORBES: Connect

In the latest census, in 1999, immigrants numbered 4.3m and made up some 7.4% of the population (overseas territories excluded), a proportion that France's national statistics office reckons has been more or less constant for a quarter of a century.

ECONOMIST: France, race and immigration