diff --git a/core/modules/update/update.report.inc b/core/modules/update/update.report.inc
index 0161647..3534a33 100644
--- a/core/modules/update/update.report.inc
+++ b/core/modules/update/update.report.inc
@@ -27,7 +27,7 @@ function template_preprocess_update_report(&$variables) {
   $last = \Drupal::state()->get('update.last_check') ?: 0;
 
   $variables['last_checked'] = ($last != NULL);
-  $variables['time'] = \Drupal::service('date')->formatInterval(REQUEST_TIME - $variables['last']);
+  $variables['time'] = \Drupal::service('date')->formatInterval(REQUEST_TIME - $last);
   $variables['link'] = \Drupal::l(t('Check manually'), 'update.manual_status', array(), array('query' => drupal_get_destination()));
 
   $rows = array();