How many rodents are there in the world, and how many are tested on each year?

I needed to know this for an english project, on animal testing, and i need this info in my introduction by tomorrow...How many rodents are there in the world, and how many are tested on each year?
alot and only rats and mice are tested on lol.How many rodents are there in the world, and how many are tested on each year?
There are around 2,000 species of rodents, and there are only 4500 species of known mammal, so almost half of all mammal species are rodents!








As for how many individuals in the world, I have no idea. In New York City, where people love to pretend that there is a rat for every person, any real scientific look into rat populations has shown there are around 300,000 rats in NYC (not millions, like some say).





But being over 2,000 species of rodent, you can't use rodents as posterboys for animal testing, they're as diverse as a mouse to a porcupine.








regardless, this is directly from Wikipedia:





[edit] Numbers


In the UK in 2004, 1,910,110 mice, 464,727 rats and 37,475 other rodents were used (84.5% of the total animals used that year). In 2005, the total number of rodents used was similar to the previous year: 1,955,035 mice, 414,335 rats and 40,856 other rodents.





In the U.S., the numbers of rats and mice used are not reported, but have been estimated at 15-20 million.[1] In 2000, the Federal Research Division, Library of Congress, published the results of an analysis of its Rats/Mice/and Birds Database: Researchers, Breeders, Transporters, and Exhibitors.