If you check the official government reports, you'll see it's actually the other way around.

2016 H-1Bs [1] - 398718 submitted with 53456 denied = 13% denial rate

2017 H-1Bs [2] - 403675 submitted with 37993 denied = 9% denial rate

So it looks like the denial rate has actually decreased.

[1] https://www.uscis.gov/sites/default/files/USCIS/Resources/Re...

[2] https://www.uscis.gov/sites/default/files/files/nativedocume...