I CM is moment of inertia of a circular disc about an axis (CM) passing through its center and perpendicular…

${\mathrm{I}}_{\mathrm{CM}}$ is moment of inertia of a circular disc about an axis (CM) passing through its center and perpendicular to the plane of disc. ${\mathrm{I}}_{\mathrm{AB}}$ is its moment of inertia about an axis AB perpendicular to plane and parallel to axis CM at a distance $\frac{2}{3}\mathrm{R}$ from center, where R is the radius of the disc. The ratio of ${\mathrm{I}}_{\mathrm{AB}}$ and ${\mathrm{I}}_{\mathrm{CM}}$ is $x:9$. The value of $x$ is ______.