In January 2011 the Sejm adopted the Election Code which changes, inter alia, some elements of electoral system and the procedure for election of the second chamber of parliament - the Senate. Among the most important novelties was replacing of former 40 constituencies with 2-4 members with 100 single-member constituencies. An election formula has remained intact; it is still a simple majority vote. As regards the adjustment of the size of constituencies (i.e. the number of seats to be taken in a constituency) to the number of inhabitants, the former electoral law provided for a relatively imprecise procedure of distribution of seats between 16 provinces and, then, between constituencies. The Election Code introduces single-member constituencies; therefore it requires that the boundaries of constituencies (and, as a result, the number of its inhabitants) be adjusted to the number of seats, i.e. one seat. To prevent the necessity of changing the boundaries of constituencies in every election, the Code provides a margin of flexibility: to each constituency it should fall at least 50% of the norm of representation and no more than 200% of that norm (the norm of representation equals to the number of the country's population divided by 100). The Code also includes a provision guaranteeing that the number of constituencies created in each province will be no less than the integral number resulting from division of the number of inhabitants of the province by the norm of representation. One possible result of the introduction of single-member constituencies is that the most represented party will lose some seats to smaller parties or to independent candidates. Should the election of 2007 be held on the basis of the Election Code, the Civic Platform would probably lose 4 seats to the Law and Justice Party. Another effect of changing the size of constituencies will be solving the problem with wasted votes. Previously, under multi-member constituencies, a voter was able to (but didn't have to) choose as many candidates as was the number of seats to be obtained in the constituency. However, the voters have not always made use of that possibility. The bigger was the number of seats to be obtained in a constituency, the smaller was the proportion of voters indicating the whole possible number of candidates. During the elections in 2001, 2005 and 2007, about 24% of votes were wasted in this way. The Election Code has filled the loopholes in the existing law. Previously, the law has not provided for what to do when the number of candidates standing for a seat in a by-election equals the number of seats to be obtained in that election. In practice, elections were held, but voters had no opportunity to vote against candidates. By contrast, the Code provides for the possibility of casting a negative vote.