Clustered Cepheid fraction as a function of Cepheid age estimated using the period-age relations for solar metallicity (Anderson et al. 2016b). The size of the error bars illustrates the full range of possible fractions. Different numbers of bins were used to illustrate the dependence on binning. Young long-period Cepheids are rare within 2 kpc of the Sun, increasing the scatter at ages below 80 Myr. No Cepheids older than 132 Myr are found in clusters within 2 kpc of the Sun.