Hello there :))
Your answer would be 1802790 people and round that... (u round)
1. take 1821000 and multiply that by .2% that will give you 3642
2. 5 years would be 5 times 3642, to find how many people being decreased. that will give you 18210
3. take your beginning total 1821000 and subtract it by 18210, and you get 1802790 people.
4. DONT FORGET TO ROUND IT. (I'm not rounding)