A one-unit increase in $X$ is associated with a $\beta_1$ unit increase in $Y$.

A one-unit increase in $X$ is associated with a $100\beta_1$ percent change in $Y$.

A one-percent increase in $X$ is associated with a $\beta_1$ percent increase in $Y$.

A one-unit increase in $X$ is associated with a $\ln(\beta_1)$ change in $Y$.