The 2016 presidential campaign has inspired voter strong interest, but as the two major political parties prepare for their respective nominating conventions, satisfaction with the candidates is the lowest it's been in decades, the Pew Research Center said Thursday.

The center's analysis offers a bleak picture of voters' impressions of the presidential campaign and the choices they face in November.

While both Hillary Clinton and Donald Trump continue to draw thousands to their respective campaign rallies, fewer than half of registered voters in both parties — 43% of Democrats and 40% of Republicans — say they are satisfied with their choices for president, the Pew Research Center said.

What's more, the center found that about four-in-10 voters (41%) say they will have a difficult time choosing between Trump and Clinton because they believe neither would be a good president.