Central non-vanishing of Dirichlet $L$-functions

We prove that, for every sufficiently large modulus $q\not\equiv2\bmod4$, at least $3/8-o(1)$ of the primitive Dirichlet characters $χ$ modulo $q$ have $L(1/2,χ)\ne0$. We also establish stronger proportions for moduli $q$ satisfying certain arithmetic conditions.