Statistics' 2016-based National Population Projections indicated that, if recent trends continue, the UK's population would increase by 3.6 million between mid-2016 and mid-2026. This represents an average annual growth rate of 0.5%. Over the same period, the population of England is projected to grow by 5.9%; for Wales, this figure is 3.1%, while for Scotland and Northern Ireland the figures are 3.2% and 4.2% respectively. These projections did not allow for any possible effects of the UK leaving the European Union. Fertility Since 1838, it has been compulsory to register a birth or death in the United Kingdom. First official data on the fertility rate of the country was first made available in 1938, However estimates of the total fertility rate can be made back all the way till 1541. The fertility rate of the country before the 19th century maintained itself at an average of around 5 children per woman. This fertility rate within the United Kingdom has been falling since 1870, when the country began into transition into the 3rd stage of the demographic transition. This transition represents the change in reproductive strategy from how many children a mother 'needs' to more of how many she 'wants' and a substitution of quality over quantity in the offspring produced. From the 1880s onwards, the birth rate began to decline rapidly from the levels it had previous sustained itself at. In England this crude birth rate decline represented a 44% decrease over a period from 1875 to 1920. A number of factors have been argued to have contributed to this ranging from four broad spectrums of biological, technological changes and developments in the society, socio-economic reasons and cultural considerations. In the context of the Industrial Revolution, a large number of socio-economic developments occurred; large scale urbanisation of the population caused mass internal movements of people to high density population centres, income per capita of citizens rose significantly especially in the last half of the 19th century, coupled with large scale economic growth improved the livelihoods of the working and middle classes of the United Kingdom, this growth in the standard of living led also to the collapse of mortality rates, which had been in decline since the early 18th century and more especially the infant mortality. This development came about with the decline of child labour at the same time as well which meant there was less of a need