Trump's leaked tax return reveals how 'The Apprentice' helped make him a lot richer

President Donald Trump's recently released 2005 tax form may not have been the smoking gun of financial insight some had expected, but it does give us a look at just how important NBC's "The Apprentice" was for him.

"The Apprentice," Trump's reality competition television show with the premise of filling a coveted job at one of his companies, premiered in 2004 on NBC. It was the result of a nearly 16-year relationship between NBC and Trump, and it premiered a year after then-NBC president Jeff Zucker and "Survivor" producer Mark Burnett began discussing TV show ideas with Trump.

But what does this have to do with Trump's return?

CBS News asked accountants to look over the released form. They found that it appears to reveal that Trump paid significantly less money in taxes in 2004 than he did in 2005. That suggests that he made siginificantly less money in 2004: an estimated $60 million in the year before versus the $152.7 million in 2005. That represents a 154.5% increase in income for Trump in one year.

It's also worth noting that in the same year "The Apprentice" premiered, Trump's infamously ailing casino empire filed for bankruptcy protection as a result of billions of dollars in debt.

Reports about Trump's hosting salary in the earliest days of show range from $50,000 to $1 million per episode. Either way, his 50% ownership of "The Apprentice" would have brought him in a sizable pile of cash over the years, and some of that would be reflected in the tax return, since the show debuted in 2004 to a hit-making average viewership of 21 million people, and the show's second season aired in late 2005 with an average 16 million viewers.

At the time, Fox News also credited the show with providing Trump additional income from merchandise sales and promotion of Trump properties, as well as helping his book, "How to Get Rich," become a bestseller.

One CBS accountant made clear that there's really no way to identify the exact sources of Trump's huge financial windfall in 2005 from the two-page Form 1040, because it doesn't reveal a breakdown of his income, just the total.

But it's certain that a significant portion of the incredible increase in income comes from earnings off of the NBC reality show and Trump's heigtened earning power as a result of it, which helped him in years to follow.

Trump famously stepped down from his "Apprentice" hosting gig as he started running for president in 2015 (NBC claimed it fired him). But he still serves as an executive producer - and presumably still gets a share of profits on the show, which recently finished a season hosted by Arnold Schwarzenegger. Though he still has a role on the show, that didn't stop Trump from lampooning Schwarzenegger for his lower ratings.