Below is an ongoing resource list of the viewership numbers for a television broadcast for WWE's Raw and SmackDown, NXT, IMPACT and AEW. The numbers below are the average viewership for the entire broadcast. You can also find Fightful's constantly updated injury report at this link and of wrestling contract expiration dates at this link.
Below are links to individual shows' viewership numbers
WWE Raw
WWE Smackdown
WWE NXT
AEW Dynamite
AEW Rampage
IMPACT Wrestling