Index problem for MS sql server 7?

Hello, I have the first column of the table (named “ID”) as primary key for the table, and define it as auto increased number start from 1.

So when I design the table, I set for ID column

Identity ticked Indentity seed =1 and Indentity Increase=1

But after I insert more than 10 values, the first column has some errors generated

The sequence is disordered and the records are like

1, 2, 3, 4,…11, 12, 15, 13,14 …

Does any one who could help with it? And how should I do to make the records are inserted according to the index order of 1,2 3,…

Thanks a lot in advance!