of labour. But it's equally true that, by consuming and bringing families who consume, they also add to the demand for labour – usually by more." Overall, Gittins has written that the "economic case for rapid population growth though immigration is surprisingly weak," noting the diseconomies of scale, infrastructure costs and negative environmental impacts associated with continued immigration-driven population growth. Robert Birrell has asserted that high immigration levels are being used by the Federal Government to stimulate aggregate economic growth, but that per capita growth is more important to Australians. Birrell concluded that high migration does not benefit existing residents, because it dilutes the benefit that can accrue from the export of non-renewable resources which form a large part of the Australian economy. As well, Birrell argues that a slowdown in labour force growth would require employers to pay greater attention to training, wages and conditions of workers. Social cohesion The impact that immigration has on social cohesion in Australia is not clear. According to a 2018 report by the Scanlon Report, between 80 and 82% of Australians felt that immigration had a positive impact on Australian society. Australians under the age of 30 were twice as likely to feel positively about immigration as Australians over the age of 60 were. A follow-up report in 2019 found that 85% of Australians polled felt that multiculturalism had made a positive impact on Australia, but 40% admitted negative or very negative feelings towards Muslims. Politics and public debate Over the last decade, leaders of the major Federal political parties have demonstrated support for high level immigration (including John Howard, Peter Costello and Kim Beazley). There was, overall, an upward trend in the number of immigrants to Australia over the period of the Howard Government (1996–2007). The Rudd Labor Government (elected 2007) increased the quota again once in office. In 2010, both major parties continue to support high immigration, with former Prime Minister Kevin Rudd advocating a 'Big Australia'; and Opposition Leader Tony Abbott stating in a 2010 Australia Day speech that: "My instinct is to extend to as many people as possible the freedom and benefits of life in Australia". On 7 August 2018, the Australian Bureau of Statistics population clock reached 25 million 33 years ahead of predictions, with 62% of the growth in the last ten years being a result of immigration. In 2003, economist Ross Gittins, a columnist at