how to add space between radiobuttonlist which is created dynamically in code behind

how to add space between radiobuttonlist which is created dynamically in
code behind

Im creating radiobuttonlist accordingly. I want space in between them. All
are done in code behind.
RadioButtonList ddlst1 = new RadioButtonList();
for (int k = 1; k < 5; k++)
{
ddlst1.Items.Add(k.ToString());
}
ddlst1.SelectedValue = i < choice1.Count() ? choice1[i] :
string.Empty;
ddlst1.RepeatDirection = RepeatDirection.Horizontal;
ddlst1.AutoPostBack = false;