User998287339 posted
Change the Type from "Integer" to "double". Hopefully this should help.
<asp:TextBox ID="txt_Ratio"
CssClass="form-control"
runat="server"></asp:TextBox>
<asp:RegularExpressionValidator
ID="rev2"
runat="server"
ErrorMessage="Value can consist of Numeric Digits Only!"
Display="Dynamic"
ToolTip="Enter Numeric Digits Only "
ControlToValidate="txt_Ratio"
ValidationExpression="^([1-9]\d*|0)(\.\d{1,2})?$"></asp:RegularExpressionValidator>
<asp:RangeValidator ID="rv2"
CssClass="Validators"
Display="Dynamic"
MinimumValue="0"
MaximumValue="100"
Type="double"
ControlToValidate="txt_Ratio"
runat="server"
ErrorMessage="Range 0 to 100"></asp:RangeValidator>