Eli Lilly and Co. said the price it was paid for its Humalog insulin dropped 8.1% over the last five years after accounting for rebates and discounts, The Wall Street Journal reported March 24, citing information from the company.

The Indianapolis-based company said the net price for the widely-used insulin drug — the price after discounts and rebates — fell to an average of $135 a patient a month in 2018 from $147 in 2014, according to the report. Meanwhile, the product’s average list price rose 51.9% to $594 per patient monthly, the Journal reported.

Drugmakers like Lilly are facing scrutiny in the U.S. Congress over big increases in insulin drug prices.