For anyone just googling "HYG" and seeing a flat chart (with a dip at the end), use a tool like Portfolio Visualizer to see the effect of bond ETF dividends.
Put "HYG" under ticker, set it to 100% and make sure to set Display Income to "Yes". You'll get compound annual growth rate (4.52%) and the inflation adjusted value (2.76%) as well.
That's not the yield, but the long-term growth rate, accounting for defaults. But yes, for a while 5% was a typical junk bond yield. As of last month, though, it shot up to ~8 percent, or 10 for B-grade.
https://www.portfoliovisualizer.com/backtest-portfolio