I found a website called Christendom Restoration that graphed vocations before and after the Council, as seen above. It used very advanced calculus on the growth of American seminarians versus years, such as S(t)=47247.8e -0.0846t and S(year) = 47247.8e -0.0846(year-1965) in order to reveal only significant statistics. The above chart shows the Pre-Conciliar and Post-Conciliar Growth functions of seminarians in the United States. As you can see, it uses “Springtime” in a sarcastic sense for what has happened since 1965.
Earlier this year. Fr. Z posted the above graph. Notice again that American priests were on the rise until Vatican II. After that, it tanked…
…not so for tradition in the United States…
The above was posted by Liturgy Guy and it shows the growth of Latin Masses in the United States. Of course, none of this is sustainable if there are not priests interested in learning the traditional sacraments.
…but thankfully, there are many coming down the pipeline, at least proportionately to the rest of American dioceses…
The above graph reveals the increase in vocations to the FSSP.
Then, the above graph reveals the increase in vocations to the SSPX from 1970 to 2020. Some people will criticize this by saying “Trads are self-selective.” Yes, that has been true for every religion for thousands of years. (The only “religions” not “self-selective” are ones that convert by the sword, like Islam.)
None of this is to say that the TLM communities (lay or religious) are without their problems or sins. But it does reveal that a good man is only going to be celibate if he has motivation to do so. This is the baked-in self-adjusting system of the Catholic priesthood for 2000 years in seeking straight, strong, celibate men. That is, for a young man honestly capable of having a family, there are only two reasons he would give up the joys of marriage: 1) Serious worship and 2) The salvation of souls.
Both can only be executed by men who are more interested in holiness than popularity, at least in any long-term analysis of the Catholic Church outside times of crisis. In normal communities, any young man can sense if his parish priest if he is seeking Christ or popularity.
Thus, a parish priest attempting to be “relevant” (or hip or cool or funny or cute or poetic) will paradoxically lose vocations, at least in the long run. The priesthood is also a participation in the victimhood of Jesus Christ. Thus, a sacrificial man will seek ancient worship and sacraments effecting the salvation of souls who would otherwise be lost. Absent this motivation, there is no need for a rightly-ordered man to be a celibate entertainer.
And that is why traditional vocations are already outdoing diocesan vocations in places like France. In fact, that is true not only in proportion of new priests to Mass-attending lay Catholics, but even gross numbers of vocations to SSPX and FSSP are outweighing every diocese in France at this point in 2023. I suspect the USA will follow.