I just watched a presentation about the acceleration of the Universe by Perlmutter. At this moment in the video he points the correct line for the scale factor of the Universe. Aaaaand that lines starts around 15 billion years ago, not 14 billion. So I thought maybe the latest estimations of the age of the Universe are now closer to 15 billions, but internet says the Planck mission gives an age of the Universe of around 13,8 billion years. So, why the line Perlmutter points as correct is the one starting 15 billion years ago, and not the next line starting a bit after 14 billions years ago ? A very similar figure (but with less data points) is also available here on the Supernova Cosmology Project official website.