On 1 December 1918, the State of Slovenes, Croats and Serbs merged with Serbia, becoming part of the new Kingdom of Serbs, Croats, and Slovenes; in 1929 it was renamed the Kingdom of Yugoslavia. The main territory of Slovenia, being the most industrialized and westernized compared to other less developed parts of Yugoslavia, became the main centre of industrial production: Compared to Serbia, for example, Slovenian industrial production was four times greater; and it was 22 times greater than in North Macedonia. The interwar period brought further industrialization in Slovenia, with rapid economic growth in the 1920s, followed by a relatively successful economic adjustment to the 1929 economic crisis and Great Depression.