Why 6.9 and not 7m?

Why did they use the figure of 6.9 M instead of a round figure of 7 M?

After all it's only an estimate.
Please take out your calculator:
Since the population will grow from 5,300,000 to 6,900,000
from 2013 until 2030 ( 18 years )
6,900,000 minus 5,300,000 = 1,600,000
Divide it by 18 years and see what you get!!

------>88,8888888888......HUAT AH!

If you use 7,000,000 minus 5,300,000 =