Buoyant consumer spending

In reviewing investment options I came across Vanguard's index fund¹ for tracking consumer discretionary stocks. Recently its largest holdings have been Amazon, Home Depot and McDonald's. I was surprised to see that in the two years from the start of September 2016 its value rose from below $123 to above $180. I would not have expected such impressive performance. Because I do not understand the fund's behavior I shall not invest in it but I wonder what the underlying story is.

¹NYSE ticker symbol VCR