If privacy is your only concern, I would suggest you use DuckDuckGo: a search engine that respects their users' privacy and that do not record any user information.

You can use a similar syntax to what you suggested:
https://duckduckgo.com/?q=site%3Awikipedia.org+%25s

If privacy is your only concern, I would suggest you use DuckDuckGo: a search engine that respects their users' privacy and that do not record any user information.

You can use a similar syntax to what you suggested:
https://duckduckgo.com/?q=site%3Awikipedia.org+%s

If privacy is your only concern, I would suggest you use DuckDuckGo: a search engine that respects their users' privacy and that do not record any user information.

You can use a similar syntax to what you suggested:  https://duckduckgo.com/?q=site%3Awikipedia.org+%25s

If privacy is your only concern, I would suggest you use DuckDuckGo: a search engine that respects their users' privacy and that do not record any user information.

You can use a similar syntax to what you suggested: 
https://duckduckgo.com/?q=site%3Awikipedia.org+%25s