Woocommerce, where to edit order totals

Wordpress/Woocommerce generates the following code on the checkout page and in the confirmation emails:

<tfoot>
        <tr class="cart-subtotal">
            <th>Zwischensumme</th>
            <td><span class="woocommerce-Price-amount amount"><bdi><span class="woocommerce-Price-currencySymbol">CHF</span>&nbsp;113,70</bdi></span></td>
        </tr>
        <tr class="woocommerce-shipping-totals shipping">
            <th>Versand</th>
            <td data-title="Versand">
                <ul id="shipping_method" class="woocommerce-shipping-methods">
                    <li><input type="hidden" name="shipping_method[0]" data-index="0" id="shipping_method_0_flat_rate1" value="flat_rate:1" class="shipping_method"><label for="shipping_method_0_flat_rate1">Vinolog: <span class="woocommerce-Price-amount amount"><bdi><span class="woocommerce-Price-currencySymbol">CHF</span>&nbsp;15,00</bdi></span></label>                 </li>
                </ul>
            </td>
        </tr>
        <tr class="order-total">
            <th>Gesamtsumme</th>
            <td><strong><span class="woocommerce-Price-amount amount"><bdi><span class="woocommerce-Price-currencySymbol">CHF</span>&nbsp;128,70</bdi></span></strong> <small class="includes_tax">(inkl. <span class="woocommerce-Price-amount amount"><span class="woocommerce-Price-currencySymbol">CHF</span>&nbsp;9,20</span> Mehrwertsteuer)</small></td>
        </tr>
    </tfoot>

I need the VAT part in the order-total to be displayed as a fixed percentage as opposed to the calculated absolute value.

so this part:

(inkl. <span class="woocommerce-Price-amount amount"><span class="woocommerce-Price-currencySymbol">CHF</span>&nbsp;9,20</span> Mehrwertsteuer)

would then be printed out like this:

(inkl. 7.7% Mehrwertsteuer)

Any hints on where I would be able to edit this accordingly would be greatly appreciated.

Thanks in advance.