Comparison

tygxim ... sentence correct?

No. Not quite.

The proportion of working children was higher in urban than in rural areas.

There's no need for 'recorded' as far as I can see.

CJ

thank CJ,,

I have another question, if you dont mind..
When I am trying to distinguish between rural and urban areas, can I say like this?

"Based on types of area, the proportion of working children in urban areas is 3.15% and it is 2.17% in rural ones."

tygxim can I say it like this?

Yes, you can. However, you don't have both parts in the same order:

in urban areas is 3.15%
2.17% in rural ones

It might be easier for your reader if you put both parts in the same order:

Based on types of area, the proportion of working c

thank CJ

How about 'The highest proportion of working children was recorded in urban areas rather than rural ones.'

The highest recorded proportion of working children, 3.15%, is found in urban areas. This, surprisingly, is nearly 70% higher than the proportion found in rural areas (2.17%).

Based on types of area, the proportion of working children in urban and rural areas is 3.15% and 2.17% respectively.

'A higher proportion of working children was recorded in urban areas than in rural.' (When comparing only two categories, in this case urban and rural areas, it is correct to use the comparative adjective (ending in -er) but not the superlative, ending in -est.)