  We report the results of a systematic timing analysis of all archival Rossi
X-Ray Timing Explorer (RXTE) observations of the bright black-hole binary GRS
1915+105 in order to detect high-frequency quasi-periodic oscillations (HFQPO).
We produced power-density spectra in two energy bands and limited the analysis
to the frequency range 30-1000 Hz. We found 51 peaks with a single trial
significance larger than 3 sigma. As all but three have centroid frequencies
that are distributed between 63 and 71 Hz, we consider most of them significant
regardless of the number of trials involved. The average centroid frequency and
FWHM are 67.3 +/- 2.0 Hz and 4.4 +/- 2.4 Hz respectively. Their fractional rms
varies between 0.4% and 2% (total band detections) and between 0.5% and 3%
(hard ban detections). As GRS 1915+105 shows large variability on time scales
longer than 1s, we analysed the data in 16s intervals and found that the
detections are limited to a specific region in the colour-colour diagram,
corresponding to state B of the source, when the energy spectrum is dominated
by a bright accretion disk component. However, the rms spectrum of the HFQPO is
very hard and does not show a flattening up to 40 keV, where the fractional rms
reaches 11%. We discuss our findings in terms of current proposed models and
compare them with the results on other black-hole binaries and neutron-star
binaries.
