Sort listview by values from column

Hello everybody!

I have listview with 3 columns which represent highscore table:

Reward, Time, Name

I want to sort it by int's in Reward column. How to do it not on click column but automatically  on Form_load event

I tried 

listView1.Sorting = SortOrder.Ascending;

But it's work in 95%

One of my score sometimes is not correct rest fine.... 

Piotr Robak