Number of stars with individual abundance ratio estimates from GSP-Spec. The two sets represent the whole sample and the best quality sample (quality flags equal to zero) in grey and blue, respectively. We indicate at the top [M/H] and [α/Fe] for reference (discussed in Sect. 3.2.1). The percentages correspond to the fraction of estimates with respect to the 5 594 205 stars processed by GSP-Spec. On this scale, 1% corresponds to 40 000 stars.