The phrase "a proportion that has changed" is correct and usable in written English.
You can use it when discussing statistical data or changes in quantities over time.
Example: "The report indicated a proportion that has changed significantly since last year, highlighting the need for further analysis."
Alternatives: "a ratio that has shifted" or "a fraction that has altered".
Yet 21 percent of the country's 1.2 billion people remain undernourished, a proportion that has changed little in the last two decades despite an almost 50 percent increase in food production, according to the International Food Policy Research Institute, a research group in Washington.
In addition, around one in five children consulting because of a RTI will re-consult for the same illness episode [ 4], a proportion that has changed little over the past thirty years [ 5].
In most foods, fructose and glucose are present in equal proportion, an availability ratio that has changed little over the past 40 years.
It found that 76% agree that the country's strength is "mostly based on the success of American business", and that 90% admire people who "get rich by working hard", proportions that have changed little in two decades.
About 18% of American workers hold part-time jobs, a proportion that has barely changed in 15 years.
That's about 12 percent of the assets under management, a proportion that hasn't changed much over the last year, according to a Fitch survey of the 10 largest prime money market funds, despite Greece's financial woes.
The Sutton Trust found that more than 40% of state secondary school teachers rarely or never advised their brightest pupils to apply to either the University of Oxford or the University of Cambridge – in some cases because they thought their students would be unhappy there – a proportion that has not changed substantially since the trust asked the same question nine years ago.
… The Cooperative Children's Book Center at the University of Wisconsin-Madison School of Education, which compiles statistics about the race of authors and characters in children's books published each year, found that in 2011, just over 3 percent of the 3,400 books reviewed were written by or about Latinos, a proportion that has not changed much in a decade.
Data on private financing for LICs is sketchier, but we know that European firms implement four of every ten new investment projects in Africa, a proportion that has not changed much over the past five years.
The only aspect that has changed is the increasing proportion of personal information that is available as digital data on the Internet.
