c# objects won't go under each other

i'm making a simple login-register program, i save usernames and passwords in lists.

i'm trying to show all the usernames under each other and that it wil repeat everytime a new user will be registered.

for some reason it only shows the last user, and that's it.

            for (Int32 i = 0; i < frmLogin.reg_usernames.Count; i++ )
        {
             TextBox lbl =  new TextBox { Location = new Point(15, 30), BorderStyle = BorderStyle.Fixed3D, BackColor = Color.AliceBlue, Font = new Font(Font.FontFamily.Name, 9), ScrollBars = ScrollBars.Vertical };

            this.Controls.Add(lbl);

            lbl.Text = frmLogin.reg_usernames[i];

        }