Does Scotland's population matter to the referendum debate?
It does matter. The size and make-up of Scotland's workforce would impact how much Scotland pays in pensions; relies on migrants, and would receive in terms of a share of oil reserves.
The UK has an ageing population; pensions have to be paid for longer and more has to be spent on elderly care.
In some parts of Scotland there are proportionally more old people than the rest of the UK and that's expected to increase in the coming years.
According to National Records of Scotland, the proportion of Scotland's population that is of pensionable age is projected to increase by 2.9% between 2010 and 2035, compared with 1.7% for the UK.
At the same time, the number of people in the working age bracket isn't projected to grow as quickly in Scotland as it is in the rest of the UK.
This has implications for pensions in an independent Scotland, as a smaller workforce would have to fund the pensions of more old people.