In ascending order:

|| || |Campania|4.97| |Calabria|5.46| |Apulia |8.91| |Sicily|9.25| |Basilicata |9.44| |Umbria|13| |Abruzzo|14.11| |Piedmont|14.29| |Lombardy|14.63| |Lazio|14.99| |Tuscany|16.57| |Trentino-Alto Adige|16.72| |Veneto|16.76| |Emilia-Romagna|17.35| |Molise|17.71| |Liguria|18.28| |Marche|18.3| |Sardinia|19.53| |Aosta Valley|21.18| |Friuli-Venezia Giulia|23.87|

Source: I made this data myself using the Metal Archives and Italy: Regions and Major Cities - Population Statistics, Maps, Charts, Weather and Web Information for the estimated 2025 population. I use the standard deviation value for color coding.