BOSTON — In the state's fast-changing business climate, one Massachusetts industry continues to thrive using a tried-and-true business model: Chasing the hearts and minds of state lawmakers and other top politicians.

Political lobbying is not only alive and well on Beacon Hill, it has seen something of a growth spurt over the past decade — at least measured by the number of lobbyists actively doing business in Massachusetts.

From 2006 to 2016, the number of active lobbyists jumped by about 1,000, according to an Associated Press review of state lobbying records. While much of that increase is due to a tighter definition of what constitutes lobbying, the numbers are still impressive.

In 2016, there were about 1,550 individuals who reported working, at least in part, as lobbyists. That is more than seven lobbyists for each of the 200 state senators and representatives on Beacon Hill.

A big part of the increase is due to a law that took effect in 2009 aimed at sharpening the definition of a lobbyist.

Before the new law, an individual was not considered to be a lobbyist if he or she spent less than 50 hours lobbying — or received less than $5,000 in lobbying fees — during each six-month reporting period.

The new law tightened that to 25 hours, or $2,500.

That change — meant to better reflect the actual level of lobbying — led to a spike in the number of lobbyists reporting having worked in the state from about 750 in 2009 to more than 1,500 in 2010.

Among those identified as lobbyists are plenty of familiar political names.

They include former Republican Gov. William Weld, former Democratic House speakers Charles Flaherty and Tom Finneran, former Democratic Attorney General Martha Coakley, former Democratic Senate presidents Thomas Birmingham and Robert Travaglini, former Democratic U.S. Rep. William Delahunt, former Registry of Motor Vehicles head Rachel Kaprielian and William "Mo" Cowan, a former aide to Democratic Gov. Deval Patrick who was appointed to serve briefly in the U.S. Senate.

Beacon Hill veterans are attractive to lobbying firms for their contacts and their familiarity with the mechanics of how to nudge legislation along — or block unwanted bills from becoming law.

One recent top lawmaker to make the jump is Brian Dempsey, the former chairman of the powerful House Ways and Means Committee. The Haverhill Democrat was widely viewed as a likely successor to Democratic House Speaker Robert DeLeo when he announced last month he was stepping down to take a job as senior vice president and chief operating officer at ML Strategies, one of the state's most prominent lobbying firms.

To help blunt criticism that former top political officials are trying to cash in on their contacts when they become lobbyists, the state has a "cooling off period" during which state employees — including lawmakers — are banned from acting as lobbyists for one year after leaving state government.

Pam Wilmot, executive director of Common Cause Massachusetts, said what while the number of lobbyists in Massachusetts is large, not all fit the image that many members of the public might have of someone trying to guard the interests of industries or other powerful interests.

Wilmot, herself a lobbyist, said many lobbyists are championing public interests like civil liberties or aid for the homeless.

"I don't think that the number of lobbyists per se is an issue. It's more the kind of lobbyists we have and what they are doing to influence public policy," said Wilmot, who applauds tougher lobbyist reporting measures. "One thing it does is demonstrate the importance of the lawmaking process."

There also has been a shift in recent years in the focus of some lobbying on Beacon Hill to keep up with changes in industry.

One notable example has been in the energy sector. As the state has placed more of an emphasis on non-fossil fuel energy sources, the renewable energy sector has responded by employing more lobbying muscle.

In 2015, nearly two dozen renewable energy companies and advocacy groups poured more than $1.5 million into lobbying in an effort to get their voices heard by Beacon Hill lawmakers, according to an AP review.

Just five years earlier, in 2010, only five of the 23 companies had spent anything on lobbying.