Variation of the CO(2 − 1) integrated intensity as a function of total convolving beam size (normalized to the 16′′ value) for the three outflow velocity regimes used in the molecular survey. The intensities have been determined by convolving appropriately either IRAM 30 m Nyquist-sampled maps (blue squares) or a combined Plateau de Bure interferometer+30 m data set (red triangles). The dashed lines represent a set of fits with the form that have been used to correct the survey data for beam dilution effects (see text). The error bars represent the estimated 1-σ rms and have been calculated from the noise in the spectra using a baseline fit to the line-free channels.