For power projection, it's not just about fractions. Its about geography, it's about networks. Without those 5%, no convenient access to Africa or the Middle East, no global intelligence network, a crippled sanctions mechanism.
Speaking of the Middle East, most of us never wanted you to go there and create one mess after another for us to deal with. From the first time you went, it was always despite protests from Europe. The fact you're trying to frame your adventurism as some sort of favor to us is indicative of the hubris I'm talking about.
You already are conspiring with Russia, throwing fancy parties for our enemies on your soil. Don't think we haven't noticed.
Finally, you're underestimating the economic ties by being so focused on goods (even though 20% is a huge fraction, imagine what it would mean for any companies revenue to go down by that much!) Think about the website you're on though! Services are not even included in these 20%. Think about the consequences for the tech industry if they lose Europe as customer base!
I don't think Googling some numbers makes up for a lack of systemic reasoning. You are treating your greatest asset as a burden and we do not appreciate it.