Rule 1: 1. Percentages and statistics
Say the number, then فِي الْمِائَةِ in the hundred: خَمْسُونَ فِي الْمِائَةِ fifty per cent. In print the sign ٪ follows Arabic numerals: ٥٠٪. A share is نِسْبَةُ + genitive (نِسْبَةُ الطَّالِبَاتِ the proportion of female students), and the verbs that go with it are بَلَغَتْ reached, اِرْتَفَعَتْ مِنْ ... إِلَى rose from ... to, اِنْخَفَضَتْ fell, تَجَاوَزَتْ exceeded. Approximation uses نَحْوُ or حَوَالَيْ about before a genitive, and comparison مُقَابِلَ as against. Fractions (نِصْفٌ, ثُلُثٌ, رُبْعٌ, خُمْسٌ) and ضِعْفٌ double are nouns in construct: رُبْعُ الطُّلَّابِ a quarter of the students.
بَلَغَتْ نِسْبَةُ الطَّالِبَاتِ فِي الْجَامِعَاتِ نَحْوَ خَمْسِينَ فِي الْمِائَةِ.
balaghat nisbatu ṭ-ṭālibāti fi l-jāmiʿāti naḥwa khamsīna fi l-miʾati
The proportion of women students in the universities reached about fifty per cent.
اِرْتَفَعَ عَدَدُ الطَّالِبَاتِ مِنْ بِضْعِ مِئَاتٍ إِلَى أَكْثَرَ مِنْ مِلْيُونٍ.
irtafaʿa ʿadadu ṭ-ṭālibāti min biḍʿi miʾātin ilā akthara min milyūnin
The number of women students rose from a few hundred to more than a million.
نِسْبَةُ الْأُمِّيَّةِ بَيْنَ النِّسَاءِ نَحْوُ ثَلَاثِينَ فِي الْمِائَةِ مُقَابِلَ نَحْوِ عِشْرِينَ بَيْنَ الرِّجَالِ.
nisbatu l-ummiyyati bayna n-nisāʾi naḥwu thalāthīna fi l-miʾati muqābila naḥwi ʿishrīna bayna r-rijāli
The illiteracy rate among women is about thirty per cent, as against about twenty among men.
مُقَابِلَ + genitive 'as against'.
لَا تَتَجَاوَزُ نِسْبَةُ النِّسَاءِ الْعَامِلَاتِ خُمْسَ قُوَّةِ الْعَمَلِ.
lā tatajāwazu nisbatu n-nisāʾi l-ʿāmilāti khumsa quwwati l-ʿamali
The proportion of working women does not exceed a fifth of the labour force.
حَسَبَ تَعْدَادِ سَنَةِ ٢٠١٧ م، عَدَدُ سُكَّانِ مِصْرَ نَحْوُ خَمْسَةٍ وَتِسْعِينَ مِلْيُونًا.
ḥasaba taʿdādi sanati 2017 m, ʿadadu sukkāni miṣra naḥwu khamsatin wa-tisʿīna milyūnan
According to the census of 2017, the population of Egypt is about ninety-five million.
حَسَبَ 'according to'; مِلْيُونًا accusative singular after a compound number.