Catholics who frequent internet religion forums will know, but [the vast majority of] Catholics who attend Mass once a week will never hear about this from the pulpit unless the priest is an orthodox [vast minority, far as I can tell from my bird's eye view] priest.
Never heard about "Mercy Sunday" or the new encyclical on the Eucharist in my parish. It was detailed in the diocesan newspaper, but honestly, how many Catholics read those?
It will be interesting to see (if this passes) how the secular press plays a part in spreading the word.