The world's oldest country is about to get even older.

New figures released by the government estimate people aged 65 and older will make up nearly 40 percent of the population of Japan 50 years from now. Even more troubling, the country's population is expected to shrink by 30 percent, with birth rates showing little signs of improvement.

The forecast, conducted by the National Institute of Population and Social Security Research every five years, paints a dire picture of Japan at a time when the country is already struggling to support its elderly - roughly a quarter of the population - amid a shrinking workforce.

In the last few decades, Japan's social security budget has soared 15 percent, an increase of 1 trillion yen per year. 50 years ago, there were a dozen workers for every social security retiree. 50 years from now, there will just be one.

Complicating the issue, is Japan's dismal birthrate. Young workers have increasingly become reluctant to start families, because of financial concerns. Women are putting off marriage altogether, worried it could tie down their careers. On average, Japanese women have 1.4 children. That number is 1.9 for U.S. women, according to the CDC.

Still, researchers say the study released Monday shows the rate of population decline has slowed slightly, compared to estimates released five years ago.

There is one number that continues to go up: Japan's life expectancy. Already the highest in the world, researchers estimate life expectancy for Japanese women will increase from 86 to 91 over the next half century. The number is expected to rise from 79 to 84, for men.