To get a precise answer would require extensive research compiling data from various sources – including individual universities' placement offices, professional organizations like the Canadian Society of Petroleum Geologists (CSPG), and government employment statistics – and then performing a complex analysis. This is beyond the scope of a simple answer.
While it's safe to say a *significant* portion of geoscience graduates in Canada *do* find work in the petroleum industry (given its historical importance to the Canadian economy), the exact percentage is difficult to pin down without dedicated research. The percentage likely fluctuates based on economic conditions in the energy sector.