Corporate Interest Burden

And when one little bump
Leads to shock 
Miss a beat
You run for cover
And there's heat
--The Fixx

Ponder this chart for a minute. Baa (midtier) corporate bond yields have been in secular decline while corporate interest expense has been in secular incline.

Ever more corporate bonds issued despite lower coupons. How exactly does this work? Hint: look at over central bank interest rates policies (e.g., ZIRP, NIRP) for clues.

Consider this, despite lower coupon payments per bond to bondholders, interest expense is way up. This can only be true if corporations sell (choose one): a) small quantities of bonds of low rates, b) large quantities of bonds at low rates.

For those who have argued that it is good for companies to issue debt when interest rates are low because interest expense will also be lower, how's that working?