diff --git a/src/lib/rendering.ts b/src/lib/rendering.ts
index 369feafd60673024d9f49fc33946cea4df5a5e97..019893f37295755645eede6fe9fe65c7d1ebf13d 100644
--- a/src/lib/rendering.ts
+++ b/src/lib/rendering.ts
@@ -731,8 +731,8 @@ function generateUngroupedPercentageBar(data: Attendance): string {
 function generatePercentageBar(data: Attendance): string {
     return `
       <div class="percentage-bar grouped-bar">
-        <div style="width: ${data.present * 100 / data.sum()}%;background-color: darkgreen"></div>
-        <div style="width: ${data.noshow_excused * 100 / data.sum()}%;background-color: yellow"></div>
-        <div style="width: ${data.noshow * 100 / data.sum()}%;background-color: red"></div>
+        <div style="width: ${(data.present * 100) / data.sum()}%;background-color: darkgreen"></div>
+        <div style="width: ${(data.noshow_excused * 100) / data.sum()}%;background-color: yellow"></div>
+        <div style="width: ${(data.noshow * 100) / data.sum()}%;background-color: red"></div>
       </div>`;
 }