For the number of fleets and armies a country typically has for the win, I did a statistical analysis of that (surprise). Each country sees differing amounts of fleets in most games.
Austria: Often has between 2 and 5 fleets the entire game, it's only one of 2 countries that can solo with it's original number of fleets. Clearly, being a land-based country has it's advantages.
England: This is a very fleet-heavy country and it often has 50-60% of its units as fleets. The end games often see between 6-10 fleets, sometimes more. Since it's on an island, it will clearly need more fleets than most of the other nations.
France: This is a strangely fluid country and the ranges for the number of fleets and armies on the map is pretty broad. Most games saw an even distribution of fleets to armies (8 of each by the endgame) with typically one or two more armies than fleets overall. The fact that it can move north and south for a victory shows the need for a nice mix of fleets, but armies are necessary as well to help support fleet movement along coastal zones.
Germany: Similar to Austria, Germany is pretty army-dominant, although most games saw about 4 or 5 fleets and upwards of 7, although armies are typically the dominant unit since it often finds its centers for victory at locations that can easily be reached by land.
Italy: Another fleet-heavy country, being a peninsula, it's often found with 40-50% fleets. After it makes headway along the sea-zones, the armies are used to control certain locations that the fleets can't access easily, especially the land-locked centers like Vienna, Budapest, Munich, and Paris.
Russia: Having 2 coastlines should indicate more fleets than most countries, but this isn't often the case. Most games see Russian militaries with up to 14 armies at the end of the game while many games only saw 4-7 fleets divided between its two coasts. The only locations it really needs the fleets for is Scandinavia, England and control of Italy/Tunis.
Turkey: A slightly more army-dominant nation, it's similar to Italy in terms of unit output: 40-50% fleets and the average game sees 6 fleets and 10 armies at the end. Clearly, control of Austria and Russia require a ton of armies, but control of italy and France requires a healthy supply of fleets.
Also, the map has well more coastal centers than land-locked centers with only 7 that are accessible by armies only, and the remaining 27 can be reached by fleets along coastlines. Also, there are only 4 locations that require a fleet to access, 3 of which are in England.
For the record, England had a few games in my study where it won with 12 fleets and France and Turkey came close to that amount.