In 2015 the Tories got 36% and won a small majority.
But in 2017 they got 42% and failed to win a majority.
In 2010 Labour got 29% and got 258 seats.
In 2015 labour got 30% and got 232 seats
In 2017 Labour got 40% and 262 seats
And in 2017 they got ten percentage points higher than they did in 2010, but only got 4 more seats
With 36 percent the Tories can get anything between 300 and 340 seats.
Labour can get 30 percent, and you don't know if that means 320 seats or 360