Rest-frame 15 μm luminosity functions of IR-selected galaxies in redshift bins, in comoving volume units. The datapoints are from a Spitzer-MIPS sample selected at 24 μm by Rodighiero et al. (2010), and computed at 15 μm to minimize the K-corrections. The units in abscissa are the luminosity νL(ν) at 15 μm in solar luminosities. In ordinate these are the number dN/dlogL of galaxies per cubic comoving Mpc per unit logarithmic interval of νL(ν). The lines represent our multi-population fit to the data as discussed in Sect. 3. In particular, green dot-dashed line: type-I AGNs; cyan short-dashed line: evolving moderate-luminosity star-forming galaxies (LIRG); red long-dashed line: high-luminosity starbursts (ULIRG); lower dotted black line: quiescent spiral population. The upper black continuous line is the total predicted function.