  We follow numerically the time evolution of axisymmetric outflows driven
magneto-centrifugally from the inner portion of accretion disks, from their
launching surface to large, observable distances. Special attention is paid to
the collimation of part of the outflow into a dense, narrow jet around the
rotation axis, after a steady state has been reached. For parameters typical of
T Tauri stars, we define a fiducial ``jet'' as outlined by the contour of
constant density at 10^4 cm^{-3}. We find that the jet, so defined, appears
nearly cylindrical well above the disk, in agreement with previous asymptotic
analyses. Closer to the equatorial plane, the density contour can either bulge
outwards or pinch inwards, depending on the conditions at the launching
surface, particularly the mass flux distribution. We find that even though a
dense, jet-like feature is always formed around the axis, there is no guarantee
that the high-density axial jet would dominate the more tenuous, wide-angle
part of the wind. Specifically, on the 100 AU scale, resolvable by HST and
ground-based adaptive optics for nearby T Tauri winds, the fraction of the wind
mass flux enclosed by the fiducial jet can vary substantially, again depending
on the launching conditions. We show two examples in which the fraction is ~20%
and ~45%. These dependences may provide a way to constrain the conditions at
the launching surface, which are poorly known at present.
