Benchmark of C# 6 String Interpolation vs calling ToString() directly

Interpolated_vs_ToString.md

// Inspired by https://twitter.com/Nick_Craver/status/702693060472414208
public class Framework_Interpolated_vs_ToString
{
	private long counter = 0;

	[Setup]
	public void Setup()
	{
		counter = 0;
	}

	[Benchmark]
	public new string ToString()
	{
		return counter.ToString() + " ms";
	}

	[Benchmark]
	public string InterpolatedString()
	{
		return $"{counter} ms";
	}
}

How does it scale with the number of interpolated parameters?