From left, Sens. Chuck Schumer (D-N.Y.), Orrin Hatch (R-Utah) and Chuck Grassley (R-Iowa) confer as the Senate Judiciary Committee meets on immigration reform on Capitol Hill in Washington on May 9. All three were in Congress in 1986, when the last immigration reform bill passed. (J. Scott Applewhite/AP)

Fun fact: Twenty-one currently sitting senators voted on the 1986 immigration reform bill, the last comprehensive bill signed into law to include a path to citizenship for undocumented immigrants. Nine of them were already in the Senate, while 12 were in the House. You can see the 1986 Senate roll call here, and the House one here.

So how constant were people's votes? Well, 13 voted the same way both times: Sens. Tom Harkin (D-Ia.), Carl Levin (D-Mich.), Max Baucus (D-Mont.), and Jay Rockefeller (D-Wv.) voted yes in the Senate in both 1986 and 2013, while Sen. Thad Cochran (R-Miss.) voted no both times in the Senate. Then-Reps. Barbara Boxer (D-Calif.), Tom Carper (D-Del.), Bill Nelson (D-Fl.), Dick Durbin (D-Ill.), Barbara Mikulski (D-Md.), and Chuck Schumer (D-NY) voted yes in 1986 and again as senators in 2013, while then-Reps. Richard Shelby (D-Al., now R-Al.) and Pat Roberts (R-Kan.) voted no both times.

The other eight switched it up. Sens. Chuck Grassley (R-Ia.) and Mitch McConnell (R-Ky.) voted yes as senators in 1986 but no in 2013, while Sen. Orrin Hatch (R-Ut.) voted no as a senator in 1986 but yes in 2013. Sen. Patrick Leahy (D-Vt.) didn't vote in 1986, but voted yes in 2013. In the House, then-Reps. Ron Wyden (D-Or.), John McCain (R-Ariz.) and Harry Reid (D-Nev.) voted no in 1986, but yes as senators in 2013. Then-Rep. Dan Coats (R-Ind.) voted yes in 1986 but no as a senator in 2013.

Throw in the 2006 vote and the two 2007 votes on comprehensive immigration reform, and you get an even more complex picture. Harkin, Levin, Carper, Nelson, Durbin, Mikulski and Schumer voted yes all five times, and Shelby, Roberts and Cochran voted no all five times. But Baucus, Rockefeller and Boxer, despite voting yes in 1986 and 2013, voted no at least once in 2006 and 2007. And if you add in the votes of people who weren't in the Senate in 1986 but were in 2006, 2007 and 2013, the picture gets more complicated still.

To sort this all through, I put together the following spreadsheet with data from all five votes. I also added the votes of current House members who were in office in 1986. We don't know where they stood in 2006 or 2007, or where they stand this year, but I figured their 1986 votes might be of interest. "NA" means a vote isn't applicable, either because the person wasn't in office or because the body they were a part of didn't vote that year. "NV" means the person was in office and their body did vote, but for whatever reason they didn't vote that time around (for example, Rep. John Conyers (D-Mich.) didn't vote in 1986). And keep in mind, of course, that these are five different bills, and it's not necessarily inconsistent to, say, oppose the 1986 bill but support the 2013 one.