The "default" as some of you are calling it, is a little thing known as the British empire. The US and Canada are known to North American historians as British North America. The Anglo designation is rooted in the British empire part of the equation folks. Why? Because first Britannia ruled. Then, Britannia's descendants ruled. Who rules now? The descendants of Britannia's descendants.

Have none of you ever had a US history class? Jaysus.

BTW, the percentages of population based on ancestry aren't fixed numbers. They have changed, sometimes dramatically, over time.