"even proportion" is correct and usable in written English.
You can use it to refer to a situation in which two or more things are divided into equal parts or amounts. For example, "The professor ensured that the workload was distributed in an even proportion among the students."
It's really a personal preference: I like the smaller ones with their more even proportion of crust to crumb.
Of those 61 patients, almost an even proportion had either one or two PROFs.
Alder and cypress also have greater root density and a more even proportion of total root length from the stem as well as occupying more soil around the stem than the other species tested (Fig. 3, Table 6).
Apart from adding one ordinary person to the mix -- ordinary, that is, in the sense of "not famous" -- the new edition is very like the first, entertaining and educational in the same even proportion.
There was an even proportion of patients across disease stages.
MFI-20 has an even proportion of positively and negatively worded items that are rated on a 5-point Likert scale.
Further studies may consider expanding data collection settings and using purposeful sampling to obtain a study sample with more even proportions of each demographic characteristic.
Figure 4 shows that the differences between the assumptions and the results were large and small in roughly even proportions, whether the results were significant or not.
Mix water and white vinegar together in even proportions.
However, other studies reported unaltered proportions or even increased proportions of Treg in SLE patients and a positive correlation with disease activity [ 17, 19, 32- 34].
(In my defense, this was a traffic jam of epic proportions -- maybe even Chris Christie proportions).
