Think of it this way: A giraffe is tall. A tree is tall. -> A giraffe is as tall as a tree. -> A giraffe is likely to be as tall as a tree. The growth rate is low. A growth rate of 0.5 is low. -> A slow growth rate is as low as a growth rate of 0.5. -> The growth rate is likely to be as low as 0.5.

The growth rate is likely to be as low as .5 inches, or 1/2 inch a year. This means that something could have a slow growth rate, but it could be a a faster growth rate if their diet is better and more nutritious. The growth rate of a person's hair could be as low as .5 inch per month, but it is usually a little more than that. The growth rate of a three-year-old child is as low as 3 inches per year, but could be as high as 4 inches per year.

"_____is as______as_____ " compares two things that are similar in some way. The similarity belongs after the first 'as'. The two items belong on the opposite sides of as and as. in your sentence, the growth rate is being compared to half of one percent. So you are seeing that things can be compared to other things or numbers and concepts.