This is the first time in the chart's 115-year history that a Korean singer or group has ranked in the top 100, according to the five-member group's agency JYP Entertainment.

The group and its producer Park Jin-young, also known as JYP, held a press conference to share the news and excitement with local fans.

``The Billboard's Hot 100 is one of the toughest charts to be ranked on. The Wonder Girls is the first Asian group to enter the chart in almost 30 years,'' Park said at the event packed with reporters and photographers held at a cafe in Cheongdam-dong, southern Seoul.

``The fact that the song `Nobody' was played 65 times on the top five radio stations in the U.S. is the equivalent to 650 times on local radio. It's a miracle.''

The ranking is determined by album sales and radio airtime.

The five members also looked excited to be back home, smiling and posing for the cameras eagerly.

``It feels good to be in front of so many flashing cameras,'' Ye-eun, also known as Yenny, said.

The news of the group moving to the U.S. to boost their career was considered both an adventure and a challenge, and it was obvious the young girls had a hard time over the different language, culture and preferences.

``I remember when we first went to the U.S. and I cried myself to sleep every single day. It took a long time to adjust to the new life there, and because we didn't speak the language fluently, it was hard to meet new people. It was also scary to sing and dance in front of people we didn't know well,'' Sun-mi, or Mimi, said in tears.

Learning the language was one of the most important tasks of all, and Park explained that the girls had to go through a grueling schedule every single day.

``The girls performed for 50 shows not only in the U.S., but also in Mexico and Canada as the opening act for the Jonas Brothers. They would perform, take English lessons for six hours, promote themselves in the streets two hours before and after their performances and sleep in the buses while they moved from one location to the other,'' he said.

Many Asian artists, including Korean, have tapped into the U.S. market before, but it was hard for any of them to squeeze into the already competitive pop industry. When asked how he and the girls did it, Park explained his strategy with enthusiasm.

``We thought we needed to attract teenagers. Probably because of the Internet, they were more open and didn't discriminate against any particular race, so we worked on catching their attention for seven months. Instead of just selling albums at record shops, we signed a deal with a teenage clothing brand that has more than 1,000 shops across the U.S. We started selling the album at these stores two weeks ago, and more than 30,000 albums were purchased,'' he said.

The girls have had a busy yet fruitful year, and Park seemed happy and satisfied with their work and the outcome.

``There are no groups in the U.S. that are following the retro concept. The reason radio stations play `Nobody' is because there are no songs like it,'' Park said, adding that the girls will appear on a popular television program in November.

Local fans will have to wait for the Wonder Girls to perform in Korea, as the group will continue pursuing their dream in America for the time being. They will leave Korea after shooting a commercial and release an all-English album early next year.

``We want to surprise the people who were skeptical. Even if we fail, we want to fail while doing our best. I'm relieved that we are doing pretty well now,'' Park said laughing.

Making their debut in 2007, the Wonder Girls shot to stardom with their songs ``So Hot'' and ``Nobody.'' The five members became a sensation that attracted both male and female fans with their retro and sexy look, catchy songs and down-to-earth personalities. They moved to the U.S. this year and made headlines when they became the opening act for the Jonas Brothers' concert tour.