Well it need a power steering fluid top up for sure, that you can get at any service station in 20-30 dhs. While getting that done you can ask mechanic to look for any noticeable leak (to know why it reduced) and if they find one then you need to get that repair, may be leaking hose, fluid canister or steering pump itself.
It may be due to age, that in previous service no one topped up steering fluid and after the top up you will be just fine, if no noticeable leak found.