HMRC estimate that 1.5m individuals earning below the personal allowance in 2017-18 made workplace pension contributions via Real Time Information (RTI) using net pay arrangements. About 75% of these individuals are estimated to be female and 25% are estimated to be male.
The personal allowance in 2017-18 was £11,500.
HMRC’s Survey of Personal Income (SPI) and administrative data was used to produce the estimates. The 2017-18 SPI data (published in March 2020) is the latest year available. The SPI is updated annually.