Japanese births are on pace for the steepest drop in three decades, plunging even by comparison to the declines in recent years, despite earlier hopes that couples would ring in the new Imperial era with an addition to the family.

Total births fell 5.6% on the year in the January-September period to 673,800, preliminary data published Tuesday by the health ministry shows. The full-year total last dropped by more than 5% in 1989.

The figure includes foreign babies born in Japan, as well as Japanese babies born overseas.

The number of Japanese babies born in the country is expected to reach 870,000 to 880,000 this year -- about 200,000 less than a decade ago and the lowest on record since 1899. The official count fell to 918,000 last year from around 946,000 in 2017.

One big factor this year is that echo baby boomers -- those born during a major surge in births between 1971 and 1974 -- are all turning 45 or older this year, leaving fewer women of childbearing age. The high hopes Japan had for this generation for boosting the birth rate did not materialize. Japan's total fertility rate, or the average number of children by a woman in her lifetime, also fell for the third straight year to 1.42 in 2018.

New marriages in Japan almost doubled on the year in May, coinciding with Emperor Naruhito's ascension that month. But the number of marriages has decreased since, cooling speculation that births would rebound soon.

Some experts suggest that couples were holding off on having babies earlier this year, waiting for the start of the Reiwa era in May under the new emperor. But no consensus exists on exactly what triggered this year's crash.

Smaller communities are already deep in crisis. Not a single baby was born last year in the town of Hayakawa, near Mount Fuji, or in the village of Nosegawa south of Osaka. Dozens of municipalities recorded births in the single digits.