Task: Question Generation
Input (English): Passage: The median child birthing age was 30 and the total fertility rate is 2.1 births per woman in 2010. In Māori populations the median age is 26 and fertility rate 2.8. In 2010 the Age adjustment mortality rate was 3.8 deaths per 1000 (down from 4.8 in 2000) and the infant mortality rate for the total population was 5.1 deaths per 1000 live births. The life expectancy of a New Zealand child born in 2014-16 was 83.4 years for females, and 79.9 years for males, which is List of countries by life expectancy. Life expectancy at birth is forecast to increase from 80 years to 85 years in 2050 and infant mortality is expected to decline. In 2050 the median age is forecast to rise from 36 years to 43 years and the percentage of people 60 years of age and older rising from 18 percent to 29 percent. (The number of people aged 65 and over increased by 22 percent between the 2006 and 2013 censuses.) During early migration in 1858, New Zealand had 131 males for every 100 females, but following changes in migration patterns and the modern longevity advantage of women, females came to outnumber males in 1971. As of 2012 there are 0.99 males per female, with males dominating under 15 years and females dominating in the 65 years and older range.
Output (English): How many years passed since the early migration of 1858 to 1971 when females came to outnumber the males in New Zealand?