Senators come and go, but ketchup is forever.

This is the 20th edition of Roll Call’s list of the 50 richest Members of Congress, and while many of the names (and numbers) have changed over the decades, the Heinz family ketchup fortune that was first on the list in 1990 is still first on the list today. It is only the Senator bathed in that condiment cash that has changed. In January 1990, Roll Call first published “The Roll Call Fifty,— like the current edition a hopelessly flawed attempt to gauge the relative wealth of Members of Congress based on their vague and frequently incorrect financial disclosure forms.

Back then, the No. 1 position was held by Sen. John Heinz (R-Pa.), with a net worth estimated at about $460 million. Heinz’s disclosure form only showed assets worth a minimum of about $16 million, Roll Call reported, but Forbes magazine had done an estimate of the family’s wealth that our editors at the time felt was a fairer version of the Senator’s position among his peers.

Fast-forward 20 years. Heinz died in a 1991 airplane crash, his wife Teresa Heinz inherited his fortune, and Sen. John Kerry (D-Mass) — who in 1990 reported less than $100,000 in assets, despite being part of one of the oldest families in Massachusetts and listing three family trusts of unknown value — married the widow Heinz, restoring the ketchup fortune to the top of the Congressional money list.

We still don’t really know what the Kerry-Heinz fortune is worth, but Kerry discloses more of the assets than Heinz did, so the minimum reported value is up to about $168 million. It is safe to assume that the family’s real net worth is several times that figure.

Roll Call used to rely more heavily on third-party assessments of net worth to rank the riches of Members; now we stick exclusively to the disclosure forms because they are the only common denominator available. For several years Roll Call listed former Rep. Amo Houghton (R-N.Y.) among the wealthiest Members of Congress — his family founded Corning Glass Works in 1851. But the number we attributed to him varied spectacularly because of differences in the sources we were using to estimate his wealth. In 1990, Houghton was No. 4 with a fortune estimated at $100 million. But by 1992, Roll Call, based on reporting by Forbes Magazine, pegged his net worth at $420 million and named him the wealthiest Member.

Kerry unseated Houghton in 1996 at the top of the list after his marriage to Teresa Heinz, and at the time we estimated his net worth at about $760 million.

The history of the 50 richest also offers a testament to the fact that riches can be fleeting. In 1996 a freshman Democrat from California, Rep. Ellen Tauscher, burst onto the scene in 11th place, with a net worth of about $23 million derived largely from her husband’s position as CEO of a computer company. But by 2000 the couple had divorced and Tauscher had dropped to 18th, with estimated assets of about $15 million; a year later she was down to $10 million and 27th place. In 2002, she dropped off the list entirely, with a disclosure report stating that the value of her holdings “cannot be determined pending divorce property settlement.—

In the last disclosure form she filed before leaving Congress to join the Obama administration, Tauscher listed her 2007 assets as having a minimum value of just less than $500,000.

Overall, the cost of membership in the 50 Richest club has grown dramatically over two decades. In 1990, then-Sen. Rudy Boschwitz’s (R-Minn.) estimated net worth of $1.8 million earned him 50th place on the list (and a one-word description of his assets from Roll Call: “Plywood.—) This year, the cutoff for membership in the top 50 is around $5.4 million, up slightly over last year despite a general downward trend in the value of the top Congressional portfolios.