The Tokyo Metropolitan Government plans to survey foreign tourists on what they enjoy about the city's nightlife to better cater to their interests while encouraging them to spend more, a source said Saturday.

The central government, which is considering a similar survey, is joining Tokyo's efforts to increase tourist spending. Despite the rapid increase in tourism, the average amount spent per traveler has declined in recent years.

The metro government plans to spend up to ¥50 million ($451,000) on the survey in fiscal 2018, the source said. The results will be used to tailor the government's website to promote popular spots.

Foreign tourism surged 19.3 percent from the previous year to a record 28.69 million in 2017. The government has set a target of 40 million visitors per year by 2020, when the Olympics will be held.

Total spending rose 17.8 percent on year to a record ¥4.42 trillion in 2017. But the average per visitor fell 1.3 percent to ¥153,921 after dropping 11.5 percent the previous year. Chinese tourists account for a fourth of the total but have cut back on spending.

Having a range of nighttime entertainment options is viewed as key. The Japan Tourism Agency set up a panel last year to discuss how to encourage more tourists to visit restaurants, theaters and sporting events at night.

Spending on entertainment related to culture, sports and recreation accounts for around 1 percent of overall purchases, much lower than the 8 percent lavished on France and the 10 percent spent in the United States, the agency said.