That there are false assumptions built into almost all areas of life, around everyday mathematical skills of the population, is highlighted in the full article below (copyright: Parliamentary & Scientific Committee). You can also find links to the National Numeracy research mentioned by Professor Linton below.
Building a numerate nation: confidence, belief and skills – November 2019
Numerate nation? What the UK thinks about numbers – National Numeracy Day 2019
Numeracy for Q-Step: Assessing the numerical ability of undergraduate students in order to better support them – February 2019