HERE IS A LINK to their website. You can have a look. It's pretty interesting that they were established in 1919 by law as the "official" tractor testing lab of the United States. Lots of good reading.
To answer your question, Kubota has maybe 12 tractors on the list, Kioti and LS has none. John deere has maybe 200, Agco has maybe 1/2 as many. But all the more "traditional" brands such as Massey, Agco, Case, New Holland have quite a few tractors in the database, but JD seems to have many more than the others.
It would be nice if more manufactures participated. The lab does a good job of measuring sound, power, torque, fuel consumption and weight distribution....All the things that are widely speculated and debated on this forum.