  Since it started observing the sky, the INTEGRAL satellite has discovered new
categories of high mass X-ray binaries (HMXB) in our Galaxy. These observations
raise important questions on the formation and evolution of these rare and
short-lived objects. We present here new infrared observations from which to
reveal or constrain the nature of 15 INTEGRAL sources, which allow us to update
and discuss the Galactic HMXB population statistics. After previous photometric
and spectroscopic observing campaigns in the optical and near-infrared, new
photometry and spectroscopy was performed in the near-infrared with the SofI
instrument on the ESO/NTT telescope in 2008 and 2010 on a sample of INTEGRAL
sources. These observations, and specifically the detection of certain features
in the spectra, allow the identification of these high-energy objects by
comparison with published nIR spectral atlases of O and B stars. We present
photometric data of nine sources (IGR J10101-5654, IGR J11187-5438, IGR
J11435-6109, IGR J14331-6112, IGR J16328-4726, IGR J17200-3116, IGR
J17354-3255, IGR J17404-3655, and IGR J17586-2129) and spectroscopic
observations of 13 sources (IGR J10101-5654, IGR J11435-6109, IGR J13020-6359,
IGR J14331-6112, IGR J14488-5942, IGR J16195-4945, IGR J16318-4848, IGR
J16320-4751, IGR J16328-4726, IGR J16418-4532, IGR J17354-3255, IGR
J17404-3655, and IGR J17586-2129). Our spectroscopic measurements indicate
that: five of these objects are Oe/Be high-mass X-ray binaries (BeHMXB), six
are supergiant high-mass X-ray binaries (sgHMXB), and two are sgB[e]. From a
statistical point of view, we estimate the proportion of confirmed sgHMXB to be
42% and that of the confirmed BeHMXB to be 49%. The remaining 9% are peculiar
HMXB.
