Skew-normal reconstructed (Eq. (14)) probability density functions p_i of the 12 Bensby et al. (2013) microlensed Galactic bulge stars whose most likely age is greater than 13.0 Gyr (thin curves); and probability density function dP_T/ dt′ of the most likely oldest age T of these stars (thick curve), assuming that the true stellar ages are chosen randomly from their respective pdfs p_i (Eq. (15)). The vertical line indicates .