An interesting question. On the surface a relatively simple question but the dynamics of pilgrim movements and numbers at various geographic location at various times is actually much more complex than most people imagine.
Firstly, you have left out some crucial information that would help anyone answer your question, such as:
1 Which Camino are you referring to - I guess that we assume the
Camino Frances.
2 Which geographic area of the
Camino Frances are you asking about - the part of the
Camino Frances from Sarria to Santiago, the part from Leon to Santiago, the part from St Jean to Santiago? They are all different. Even the part of the
Camino Frances though the Meseta is different from the rest in significant numbers.
3 When during April? In 2023 Easter Sunday was on the 9th April and many pilgrims plan to enter Santiago on Easter Saturday, Sunday and Monday and so you get significant numbers on those days.
Other pilgrims use the Easter holidays to walk their Camino and so you see another smaller increase in numbers around 8 days after Easter Sunday.
This year Easter is earlier and so I would expect to see these waves of pilgrims ending in Santiago much earlier, in late March and early April.
I prefer visual information and so for me a couple of graphs helps to understand some of the complexities.
There is an excellent website
https://solviturambulando.es/en/daily-pilgrim-arrivals/ run by Solvitur Ambulando that provides this data and I recommend it to you.
I have taken the liberty of taking two screenshots from this webpage to illustrate what I have said above.
View attachment 165659
Firstly, this graph shows in a more sophisticated way what
@Bradypus suggested with his back of an envelope logic.
The graph to concentrate on is the bottom one.
At the top of this bottom graph you see a long blue line. That represents the number of pilgrims who started in Sarria and finished in Santiago during April.
Immediately below this very long line is a much shorter line representing the pilgrims who started in St. Jean and finished in Santiago during April.
There are additional, shorter lines below this representing some of the other popular starting points along the
Camino Frances.
If life was simple then the number of pilgrims starting and finishing each day would be approximately constant but life isn't simple.
The second graph below shows how the daily numbers of pilgrims finishing changed through out April.
View attachment 165660
If you look at the red area of the graph then you can see how the numbers built up from a relatively low level towards Easter Sunday, dropped down a bit and then increased again until the 15th April, dropped right off to zero on one day and then built up again towards the end of the month.
If you are planning to walk from Sarria then these numbers and these graphs will assist in answering your question but if you are planning on starting in St. Jean or even somewhere inbetween St. Jean and Sarria then these numbers are almost irrelevant because we don't have a clear picture of numbers from last year.
About the best information that we can get for the St. Jean area of the
Camino Frances is that numbers of pilgrims starting from here have historically tended to build quite quickly from very low numbers over Winter to a peak in mid May, drop down relatively quickly through June and July and then start building again in August for another peak in September then drop off rapidly.
This means that early April numbers are historically much less than late April numbers in this area.
However, last year the mid May peak moved forward around two weeks and occured at the beginning of May. We don't know if this will be repeated this year.
Finally, while we might suspect that 2023 numbers of pilgrims would give us some idea of how many people will chose to walk this year, in fact we actually have no idea how many people will walk this year, where they will start from and when they will start.
