The population in the world is constantly changing (increasing).
At around 10am GMT on 30 Nov 2017 the World Population was 7,584,713,062 and the population in the UK was 66,181,585.
Figures as of Jan 1 2017 indicate:
World Population 7,510.3 million
EU population 511.81 million
UK Population 65.8 million
EU27 population 446.01
UK accounted for 12.8% of the EU and approx 0.9% of the world
Households in the UK
In the UK there were 27.2 million households in 2017, resulting in an average household size of 2.4