Slovenia has a developed economy and is the richest Slavic country by nominal GDP, and the second richest by GDP (PPP) behind the Czech Republic. Slovenia is also among the top global economies in terms of human capital. Slovenia was in the beginning of 2007 the first new member to introduce the euro as its currency, replacing the tolar. Since 2010, it has been member of the Organisation for Economic Co-operation and Development. There is a big difference in prosperity between the various regions. The economically wealthiest regions are the Central Slovenia region which includes the capital Ljubljana and the western Slovenian regions, as Goriška and Coastal–Karst, while the least wealthy regions are the Mura, the Central Sava and the Littoral–Inner Carniola.