1 AD
2 AD
3 AD
4 AD
5 AD
6 AD
7 AD
8 AD
9 AD
10 AD
new decade starts:
11 AD
12 AD
13 AD
14 AD
15 AD
16 AD
17 AD
18 AD
19 AD
20 AD
new decade starts...
etc.
But apparently there's no world consensus on this, so we even have names for this. The above, correct method, is called "ordinal", and the tens-digit method is called "cardinal".
