Знак % вынесен в переводы, т.к. он может отличаться в других языках

src/components/languageSwitcher/LanguageSwitcher.js

@@ -185,7 +185,7 @@ class LanguageSwitcher extends Component {
         if (progress !== 100) {
             progressLabel = (
                 <Message {...messages.translationProgress} values={{
-                    progress: `${progress}%`,
+                    progress,
                 }} />
             );
         } else if (!isReleased) {

src/components/languageSwitcher/languageSwitcher.intl.json

@@ -1,7 +1,7 @@
 {
     "siteLanguage": "Site language",
     "startTyping": "Start typing…",
-    "translationProgress": "{progress} translated",
+    "translationProgress": "{progress}% translated",
     "mayBeInaccurate": "May be inaccurate",
     "weDoNotSupportThisLang": "Sorry, we do not support this language",
     "improveTranslates": "Improve Ely.by translation",