To work this out you would first need to find how many times 5% goes into 100%, You can do this by dividing 100 by 5, this gives you 20. This is because the whole amount is equivalent to 100%.
To work out the total number of readers you would multiply 70 by 20, this gives you 1400. This is because we know that 70 is equivalent to 5% and that 5% goes into 100% 20. So by multiplying 70 by 20 we are working out the total (100%), and that this shows us there are 1400 readers.
look the the left of the column asked for. if it's 0-4 it stays the same but if it's 5-9 it goes up on. e.g if the number was 97508 it would go to 98000