Really don't use 'many' or 'many of' in advance of an uncountable noun, to talk about a big quantity or level of anything. Use Substantially or Substantially of. several - a quantifier that can be utilised with depend nouns and is often preceded by `a'; a small but indefinite selection; https://travislruvw.blogmazing.com/35912556/not-known-facts-about-how-many-times-has-manchester-city-won-the-premier-league