I would think that since innovation and growth (caused by innovative use of resources or increase in efficiency or novel products and services) in general should be relative to the population and its state to begin with, nominal GDP growth per annum would be a reasonable metric as a proxy for the wildly non-measurable "innovation in terms of GDP"; for reference, here's the data for 2018:
USA: 2.9% Canada: 1.9%
Sweden: 2.2% Norway: 1.3% Finland: 1.7% Denmark: 2.4%
Germany: 1.5% France: 1.7%
Ireland: 8.2% (not a typo, likely explained by expansion of business services from NA into EU) UK: 1.4%
Portugal: 2.4% Italy: 0.8% Greece: 1.9% Spain: 2.4%