It’s not really accurate to compare hostel and hotel occupancy rates because our business models work so differently. Hotels calculate their occupancy rate by the number of rooms sold. Hostels calculate it by the number of beds sold.
If you have a 100-bed hostel, then you’ll hit 100% occupancy with 100 guests. Let’s assume those guests are divided into 4-bed dorms, so you would have 25 occupied rooms.
Now let’s assume that the hotel next door has 100 rooms. With 100 guests their occupancy rate might be 100% (1 person per room) or 50% (2 people per room) or somewhere in between. Also, the full 25-room capacity of your hostel would only constitute 25% occupancy for the hotel if you compared the rooms evenly, even though the number of guests is the same.
So the comparison doesn’t really work. It gets even less accurate when you start comparing your costs. Your 100 guests in 25 rooms will cost you far less money for electricity, heating, and staff than the hotel’s 100 guests in 50 or 100 rooms.
Of course this ignores the fact that hotels will probably attract a different clientele than your hostel, so counting their guests wouldn’t accurately reflect your potential business either.
Unfortunately that doesn’t help you choose an occupancy rate to use for your projections. The 100-room hotel is just an example to make the math easy. Did the report that you found also give you an average number of rooms for the hotels in your city? Looking at the numbers you found, if the average hotel occupancy rate is 35% in your city, then we could guestimate around 70 guests per night for a 100-room hotel. Maybe you could do a similar calculation with the real numbers to get a guess at the number of people who pass through.
I don’t know which country your hostel will be in, but maybe there are some ski hostels in the US, Canada, Europe, or elsewhere that would have similar markets and be willing to share their data. You might have better luck if you contact them directly though, because this is information that they might not be comfortable sharing openly on an international forum.
A few older threads ask similar questions. You can check them out here:
Hostel Occupancy Rates vs. Hotel Occupancy Rates?
Business plan question: Hotel -vs- Hostel occupancy statistics
Occupancy Rates/Biz Plan
I hope some of this helps a little.