Currently Ninja's viewership share on the whole Mixer streaming platform is
On Twitch in July his share was 2.2%. With the numbers he is having now on Mixer, that would be 1.6% in August on Twitch.
Overall, the Mixer's viewership is 22 times smaller than that of Twitch.
As can be seen on the charts, the proportion of concurrent streams and viewers that watch them on Mixer differ from the Twitch's one. For every live channel on Mixer there are only 3 viewers, when Twitch streamer can count on 26.9 viewers. However, Twitch has massive esports channels that pull a huge portion of its audience.
What does Ninja's average stream look like: Mixer (August) vs Twitch (July)
The first Ninja's stream on Mixer attracted in total ~2.2 million people during the 8.5 hours of broadcast. On average 61 574 people watched it simultaneously, and the peak was hit at 85 876.
The fact that Ninja attracted more than 50% of the entire Mixer audience is not a surprise - 85% of his viewership came to Mixer to watch only his stream. After he ended the broadcast, around 6% of the viewers remained on Mixer to watch other streams.
Ninja also announced on his Twitter that he had gained more than 500 000 new subscribers, though subscription is free for anyone to claim until September 30th.
For comparison, the usual Ninja's stream that could be watched in July on Twitch: 420 000 unique visitors per stream, almost 10 000 followers, 41 000 in average and 163 709 at the peak viewers concurrently (Fortnite event on July 20th). The broadcasts usually lasted for 6 hours.
Now check the biggest stream in Ninja's entertainment career that was held in March 2018. In total, 4.4 million people came to see it, an average of 197 000 spectators watched how Ninja played throughout the whole broadcast, and the peak of 617 693 viewers was hit with the appearance of Drake. That stream brought him more than 171 000 new followers.