# Which thermal expansion coefficient to use?

I wanted to solve this problem:

In a glass there is 1 liter water at $5^\circ\ C$. How much water will spill out when the system is heated to $85^\circ\ C$?

Then I thought, OK I know $V_0$ which is 1 liter and $ΔT$ is $80^\circ\ C$, and I searched for the thermal coefficent in Google. It turns out it's varying. Look at this:

So how am I going to calculate the thermal expansion? The coefficient varies from $1 × 10^{-4}$ to $6 × 10^{-4}$.