'Census Day' has already been and gone.
But don't worry if you forgot to fill out the survey or didn't have time.
The questionnaire takes place once every 10 years to give a picture of all the people and households living in England and Wales.
The Census helps organisations make decisions on planning and funding public services, including transport, education and healthcare.
The survey is recorded by the Office for National Statistics - the UK's largest independent producer of official statistics and the recognised national statistical institute of the UK.
It is mandatory, and this year's deadline was Sunday, March 21.
Because it is a legal requirement to supply the information, those who fail to complete it could be fined £1,000.
It is also a criminal offence to supply incorrect information - so be sure to be accurate.
If you have missed the deadline, then it's important to try to fill it out as soon as possible.
You can still go online where you will be required to submit your special access code. This will have been provided in a letter through the post.
If you've lost it, you can request a new one online.
According to Census.co.uk, anyone who doesn't complete the form will have a census officer get in touch with them.
They will help make adjustments for the participant to complete their document.
Further failure to comply is a crime which results in a potential court case.
More information can be found here.
