"The GDP per capita in 2008 was nearly 24 times larger than it was in the 1950s." Anything similar to that will work. However, for correct grammar, you need to add "than it was in" or something like that before 1950s. "The GDP per capita in 2008 was nearly 24 times larger than in the 1950s" is technically wrong because the comparison is between GDP in 2008 (noun) and "in the 1950s" (time). You need to have a similar comparison (noun to noun) so "The GDP per capita in 2008 was nearly 24 times larger than it was in the 1950s" compares 2008 GDP to 1950s GDP. Most people don't speak like this but it's technically wrong and something that's tested on in the writing/grammar sections of the SATs and similar tests.

The GDP per capita ( of South Korea) in 2008 was nearly 24 times bigger than in the 1950s.

ohhhhhh Thank you !! ^0^

Just use the same words in a slightly different order. (Bigger can be included or not. Better without it.) I'd write: GDP per capita in 2008 was nearly 24 times what it was in the 1950s. But ok: GDP per capita is nearly 24 times bigger in 2008 than in the 1950s.