The National Institute of Economic and Social Research (NIESR) reported that the UK economy would shrink by 3.6% by 2040 if net migration dropped to zero. This decline would stem from a smaller workforce and slower growth in new jobs. NIESR predicted the budget deficit, the gap between what the government spends and what it collects, would grow by about £37 billion by 2040. This is equal to 0.8% of the country's total economic output (GDP). As the population grows older and stops increasing, tax income would fall, forcing the government to borrow more money. The think tank noted that while individual wealth and wages might rise at first, with GDP per person up 2% by 2040, the country's overall economic growth would be weaker.