On Friday, we reported that YouTube was at the top of the list for monthly unique viewers throughout the month of May and total videos streamed.

YouTube had over 136 million unique viewers and they streamed well over 16 billion videos.

Now we’re back with some more information from Nielsen ratings group informing us that YouTube’s top five partners are supplying viewers with almost 1.5 billion monthly video streams, as measured throughout the month of May.

Vevo, Warner Music Group (WMG), Fullscreen, Maker, and Machinima make up the top five partners, and all of them work with YouTube build their audience and monetize content.

Vevo tops the list of partners with 41,000 unique monthly viewers, and almost 695,000 videos streamed throughout the month of May. Warner Music Group comes in second, but trails behind significantly with only about 22,895 visitors and 172,985 videos streamed.

Machinima takes third in the ranking and had 17,625 visitors in May and streamed almost 430,000 videos. So, not as many visitors, but a lot more videos streamed. Fullscreen, comes in fourth with 12,484 visitors and just under 80,000 videos. Maker placed fifth, with just under 10,000, but 93,588 videos streamed.

Insights on the top five YouTube Partners:

* More than half of each channel’s unique viewers were under the age of 35.

* About 1 in 6 Americans who watched online video during May 2012 streamed video on the WMG YouTube channel (almost 23 million unique viewers).

* Vevo led the top five partners in total streams (695 million), while Machinima averaged the most streams per viewer, 24 in May 2012.

* Machinima also captured the highest composition of male viewers (62.6%), while others hovered closer to a 50/50 female/male split.

* Fullscreen and Vevo skewed toward a slightly older demographic, as 15.3 and 15.7 percent of their viewers are 50 years or older, respectively.

* Maker drew 9.7 million unique viewers who averaged nearly ten streams per viewer.

So there you have it, YouTube still reigns supreme as an online streaming video provider. They continue to find new ways to deliver unbelievable amounts of content and somehow pay the bills at the same time.