[Military Needs for a Peaceful Nation]

I'm just asking what ratio of military should I shoot for. Regardless of my Nation Strength or my Alliances, my soldiers will always be somewhere within 30% and 45%. Right now, all I have is soldiers and I think I need other forms of military but I don't know how much I should purchase.

[Military Needs for a Peaceful Nation]

What does a peaceful nation need to protect itself? I already have a 30%-45% soldier ratio but do I need aircraft, navy, spies, etc.? I'm not a hard core player of this game but I do check it every morning. Any help would be great.