and UDS astrometric frames. Aperture magnitudes were then extracted using a 2-arcsec diameter. Only sources outside the contaminated halos of saturated optical stars were used.

![Differential number counts of passive and star-forming BzK galaxies with apparent K-band magnitude, compared with the full-sample of $K$-selected galaxies. The error-bars shown are standard Poisson errors on the counts. Two sets of values are shown for pBzKs: the standard selection of pBzKs (filled, red triangles); and the worst case sample described in the text (open, green triangles). Numerical values are reproduced in table \[tab-counts\]. Literature values from K06 and [@Blanc_etal:2008] are also shown (dot-dashed lines and dashed lines respectively). The plateau identified in previous works (K06, L07, @Blanc_etal:2008) and subsequent turn-over prior to our magnitude limit are apparent in the pBzK number counts.[]{data-label="counts"}](PSfiles/DR1_bzk_K_number_counts_worstcase.ps){width="240pt"}

All K-band sources with $K_{AB} < 23.5$ were used for BzK selection unless both the B- and z$^{\prime}$-band magnitudes were fainter than the $3
\sigma$ limits measured on those images ($0.29\%$ of sources outside of contaminated regions), since these cannot be constrained within the BzK plane.

Overall this procedure results in the selection of 15177 sBzKs (21.7% of the full sample) and 742 pBzKs (1.06 % of the sample), 11551 and 