You will need to remove runat attribute from here if you want to set the inline width like below:
<div id="Percent" class="bar bar-warning" style='width: <%# DataBinder.Eval(Container.DataItem, "number") %> %'>
Otherwise you can set it from code behind:
<div id="Percent" runat="server" class="bar bar-warning" >
Percent.Style.Add("width", "YourDatabaseValue");