Eucs, in general, are much faster growing than most other trees in cultivation. Most euc species can be expected to achieve 6 - 12 feet of new growth each year. Exceptions include some of the snow gums (E. pauciflora and its subspecies, E. gregsoniana, etc.), which usually take a couple years to establish, during which they may only grow a foot or two each year; and a few other unique species such as E. vernicosa, E. stricta, etc. which are quite slow growing. (These exceptions are all noted in the euc species index.) But even many of the snow gums will pick up to 4 - 6 feet per year once they are well established.
So, if you have planted a large or rootbound euc, and you are pleased that it has grown 3' in one year, you should not be (in the opinion of this euc grower). Because if you had planted a small one, it would grow much faster. 3' per year may be an acceptible growth rate for many ornamental trees, but for most euc species it is quite pathetic.