Many Frobenius complements have even order

The theory of Frobenius groups with Frobenius complements of even order largely reduces to tractable algebraic number theory. If we consider only Frobenius complements with an upper bound $s$ on the number of distinct primes dividing the order of their commutator subgroups, then the proportion of these with odd order is less than $1/2^{s}$. A positive lower bound is also given.