Out of $1500$ students, $480$ are enrolled in NCC. What percentage of students are not enrolled in NCC?

1. Total number of students = $1500$
2. Number of students enrolled in NCC = $480$
3. Number of students not enrolled in NCC = $1500-480=1020$

Now, calculate the percentage of students not in NCC:

$$\text{Percentage}=\left(\frac{1020}{1500}\right)\times 100\%$$

$$\text{Percentage}=\frac{1020}{15}\%=68\%$$