I posted an article about this topic just recently:

The wealthier Middle Eastern countries had birth rates around six or seven children per woman, but the United Arab Emirates “has a birth rate now that is lower or about the same as baby-scarce Japan,” dipping “to about 1.2,” Goldin said, while the birth rate in Saudi Arabia is 2.3.

“When you look at what these birth rates were for just the previous generation, it’s astronomical change,” she said.

The global shift, she continued, can be traced to one common cause: the increased agency of women, who during the last century became increasingly able to opt out of traditional family roles to pursue other options, such as education and careers.

“Wherever you get increased agency, you get reduction in the birth rate,” said Goldin. “The central cause arises when women have autonomy and have the ability to be educated, to have occupations and careers.”

Here's the full paper called "The Downside of Fertility"

You said there are no stats and there are. That's what I responded to - the stats are showing the trend of women's freedoms tied to the falling birth rates. And since women have more options to delay children or not have them at all, the economy will play a factor into them using those options that are available. And despite the economic hardships, women overall are not going to choose to have as many children as they did before gaining those freedoms and medical advancements.

I don't think it's helpful to discuss falling birth rates without acknowledging that access to education, career advancements, and reproductive health options have a huge impact. That's one of the reasons conservatives across the globe are pushing to limit abortion access and take away birth control.