  The D-wave state component of the neutron-proton bound state in the deuteron
is calculated in the Nambu-Jona-Lasinio model of light nuclei - the
relativistically covariant quantum field theoretic approach to the description
of low-energy nuclear forces. The theoretical value of the fraction of the
D-wave state relative to the S-wave state is equal to eta_d = 0.0238. This
agrees well with the phenomenological value eta_d = 0.0256(4) quoted by
Kamionkowski and Bahcall (ApJ. 420, 884 (1994)).
