Which regression form to use

Hi all,

I have an independent variable which ranges from 0 - 1 in theory, but has a practical range of 0.18 to 0.67. When using a normal linear regression, it calculates the effect of a one unit increase in x. However, here that is unrealistic and as such, tells me nothing. How should I transform my variables to get a correct, interpretable result?

Kind regards,
Maarten