As of July 21, 2018, PolitiFact ranks Trump as telling mostly false statements to “pants on fire” lies 69% of the time.
Check out the latest fact checking here, along with all the details:
http://www.politifact.com/personalities/donald-trump/

The New York Times Rates LIES of Trump vs. President Obama – In his first 6 months, Trump told nearly SIX TIMES as many falsehoods as Obama did during his ENTIRE PRESIDENCY

Check out all the details and fact here:

https://www.nytimes.com/interactive/2017/12/14/opinion/sunday/trump-lies-obama-who-is-worse.html