Vector quantization is a technique used in (usually lossy) data compression. The basic idea is to code a multidimensional vector space into a sub-space with lower dimension. The lower-space vector requires less storage space and the data is thus compressed. The transformation into the sub-space is usually achieved through projection or by using a code-book.
... spread out with 20.6% under the age of 18, 5.0% from 18 to 24, 26.8% from 25 to 44, 27.7% from 45 to 64, and 19.9% who are 65 years of age or older. The median age is 43 ...