Third Research

My topic
: Human soldiers are more effective than military robots.
What I want to learn from this source
:How many nations have made military robots now
Notes
Before researching this, I have known that tank, or bomb can also be the military robot. Therefore, I'll change the meaning of the question a little bit. It means that now how many nations have developed the military robot? and how much they are developing it.

*I was trying to research the chart or the graph of some countries robot development eagerly. To my disappointment, however, I could not find it.
 But all relevant articles say that U.S military has led to the development of it. Actually, the ultimate purpose of this question is to know how the nation use the military robot. Therefore, though I can not find the exact data, I accomplish the ultimate purpose.
Final thoughts
: As a results, I could not find the files. But I could realize many nations are now trying to make and develop military robots while researching.