  Gram's Law describes a pattern that frequently occurs in the distribution of
the non-trivial zeros of the Riemann zeta function along the critical line.
Whenever Gram's Law holds true, it reduces the difficulty of computing the
corresponding zeta zeros. In this paper, we provide a model that estimates how
often this pattern occurs. The model is based on a conjecture that relates the
statistical distribution of the zeta zeros to that of the eigenvalues of random
unitary matrices.
