help me crack a simple time code

[Unabridged]

30989 corrisponds to 10/3/05
30111 to ~ 9/24/05
30000 to ~ 9/22/05
29191 to ~ 9/13/05

note: 30989 may not mean 30,989
each digit could be independant

[Girchuck]

9days ~ 800

You are going to need more accuracy to get more presize