Each physical quantity must have a unit designation. For any number it has to be very clear in which unit this physical quantity is given, it is very important. Sometimes physicists and engineers use a practice that physical quantity without a unit is accepted as a value in basic units by default. But sometimes different groups in common work understand defaults for units of measurements in different ways. These cases bring catastrophes with human victims and many million dollars loss. Read about catastrophes because of units of measurements here:
https://www.mentalfloss.com/article/25845/quick-6-six-unit-conversion-disasters
https://www.simscale.com/blog/2017/12/nasa-mars-climate-orbiter-metric/
So units for data very mandatorily have to be:
- in texts: close to a number in the right
- in tables: at the heads (titles) of columns
- in diagrams: at the titles of the axis
