Welcome to the forums, Nia
This type of information is readily available via the ONS (Office for National Statistics) site. A bit of searching their site will help you to fine-tune to get what you need, because the data is collected with several variations. Note that these statistics are usually released around november of the following year because there is a massive job in collating, cleaning the data. The most recent data is therefore 2018
PS simply googling UK absence rates would have thrown up the relevant pages........

PS Crossed with David's post.

Hello @Nia,

Further to the guidance and valid responses provided @David and @Ray below, the latest UK workforce sickness absence reported published by the ONS, is that of 2018 (As shared by @David).

If however, you want to have access to the data source used for the 2018 reporting, use the link below.

Sickness absence in the UK labour market

All the best

Felix