I was curious why those tweets only compared rate of contribution. From the PDF source: > Prior to 2003, Russia and the United States were responsible for 97%

I was curious why those tweets only compared rate of contribution. From the PDF source: > Prior to 2003, Russia and the United States were responsible for 97% of the mass of rocket bodies abandoned in low Earth orbit (LEO). Since 2003, China and the Rest of the World are responsible for 68% of the rocket body mass abandoned in LEO. As a matter of fact, these trends over the last 20 years have resulted in China and the US now having roughly the same amount of rocket body mass in LEO. Russia is still responsible for half of the rocket body mass in LEO, down from ¾ of the total mass in LEO as of 2003. The rate that China is leaving abandoned rocket bodies in orbit reverses the improved behavior of US and Russia and results in a continual accumulation of objects that will be especially prolific in creating fragments if involved in a collision. So if I read it right, in absolute terms Russia still has about 50%, and US and China each about 25%, of the LEO abandoned rocket body mass.