Wierd execution of if condition

Else condition is executed every time. if input is '11' answer is 'f' not 'D', I know the last condition should be else if but according to the logic if input is 11 output should be 'D'

function getGrade(score) {
let grade;
var score1 = Number(score);
// Write your code here
if (score1 > 25 && score <= 30)
grade = "A";
else if (score1 > 20 && score <= 25)
grade = "B";  
else if (score1 > 15 && score <= 20)
grade = "C";
else if (score1 > 10 && score <= 15)
grade = "D";      
else if (score1 > 5 && score <= 10)
grade = "E";
else  (score1 > 0 && score <= 5)
grade = "F";
return grade;

}