$ 3.4 billion was spent in 2018 on lobbying.  In 2018,  $1 billion was spent by SuperPacs which don't have limits on how much they take in  or on how much they spend. Dark money groups don't have to say who gave the money or how much. 

https://www.commondreams.org/views/2019/04/02/money-talks-big-time