How much of the universe's baryonic mass does Helium account for compared to Hydrogen?

Roughly 24% of the baryonic mass

Helium represents the second most abundant element in the cosmos, forming directly after hydrogen during the initial moments of nucleosynthesis. While highly common, its abundance is significantly less than that of hydrogen. Specifically, helium accounts for approximately 24% of the total baryonic mass of the universe. This ratio highlights the efficiency limitations of the early universe's environment; the rapid cooling prevented the extensive fusion required to create elements heavier than helium in large quantities. Consequently, all elements beyond hydrogen and helium—such as oxygen, carbon, and silicon—collectively represent only about 1% of the universe's normal matter content.